Multi-speed dual-clutch planetary transmissions having three continuously interconnected gear members

ABSTRACT

The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least six forward speed ratios and one reverse speed ratio. The transmission family members include four planetary gear sets, two input clutches, eight or nine torque transmitting mechanisms and two fixed interconnections. The invention provides a low content multi-speed dual clutch transmission mechanism wherein the two input clutches alternately connect the engine to realize odd and even speed ratio changes. The nine torque transmitting mechanisms provide connections between various gear members, the fixed interconnections, the input clutches, the output shaft, and the transmission housing, and are operated in combinations of three to establish at least five forward speed ratios and at least one reverse speed ratio.

TECHNICAL FIELD

[0001] The present invention relates to a family of power transmissionshaving two input clutches which selectively connect an input shaft tofirst and second pairs of planetary gear sets to provide at least sixforward speed ratios and one reverse speed ratio.

BACKGROUND OF THE INVENTION

[0002] Passenger vehicles include a powertrain that is comprised of anengine, multi-speed transmission, and a differential or final drive. Themulti-speed transmission increases the overall operating range of thevehicle by permitting the engine to operate through its torque range anumber of times.

[0003] A primary focus of transmission and engine design work is in thearea of increasing vehicle fuel efficiency. Manual transmissionstypically provide improved vehicle fuel economy over automatictransmissions because automatic transmissions use a torque converter forvehicle launch and multiple plate hydraulically-applied clutches forgear engagement. Clutches of this type, left unengaged or idling, imposea parasitic drag torque on a drive line due to the viscous shearingaction which exists between the plates and discs rotating at differentspeeds relative to one another. This drag torque adversely affectsvehicle fuel economy for automatic transmissions. Also, the hydraulicpump that generates the pressure needed for operating theabove-described clutches further reduces fuel efficiency associated withautomatic transmissions. Manual transmissions eliminate these problems.

[0004] While manual transmissions are not subject to the above describedfuel efficiency related problems, manual transmissions typically providepoor shift quality because a significant torque interruption is requiredduring each gear shift as the engine is disengaged from the transmissionby the clutch to allow shafts rotating at different speeds to besynchronized.

[0005] So called “automated manual” transmissions provide electronicshifting in a manual transmission configuration which, in certaincircumstances, improves fuel efficiency by eliminating the parasiticlosses associated with the torque converter and hydraulic pump neededfor clutching. Like manual transmissions, a drawback of automated manualtransmissions is that the shift quality is not as high as an automatictransmission because of the torque interruption during shifting.

[0006] So called “dual-clutch automatic” transmissions also eliminatethe torque converter and replace hydraulic clutches with synchronizersbut they go further to provide gear shift quality which is superior tothe automated manual transmission and similar to the conventionalautomatic transmission, which makes them quite attractive. However, mostknown dual-clutch automatic transmissions include a lay shaft orcountershaft gear arrangement, and have not been widely applied invehicles because of their complexity, size and cost. For example, a dualclutch lay shaft transmission could require eight sets of gears, twoinput/shift clutches and seven synchronizers/dog clutches to provide sixforward speed ratios and a reverse speed ratio. An example of adual-clutch automatic transmission is described in U.S. Pat. No.5,385,064, which is hereby incorporated by reference.

SUMMARY OF THE INVENTION

[0007] The invention provides a low content multi-speed dual-clutchtransmission family utilizing planetary gear sets rather than lay shaftgear arrangements. In particular, the invention includes four planetarygear sets, two input/shift clutches, and nine selectable torquetransmitting mechanisms to provide at least six forward speed ratios anda reverse speed ratio.

[0008] According to one aspect of the invention, the family oftransmissions has four planetary gear sets, each of which includes afirst, second and third member, which members may comprise a sun gear,ring gear, or a planet carrier assembly member.

[0009] In referring to the first, second, third and fourth gear sets inthis description and in the claims, these sets may be counted “first” to“fourth” in any order in the drawings (i.e. left-to-right,right-to-left, etc.).

[0010] In another aspect of the present invention, each of the planetarygear sets may be of the single pinion type or of the double pinion type.

[0011] In yet another aspect of the present invention, the first memberof the first planetary gear set is continuously connected with the firstmember of the second planetary gear set through a first interconnectingmember.

[0012] In yet another aspect of the present invention, a member of thefirst or second planetary gear set is continuously connected with thefirst member of the third planetary gear set, the first member of thefourth planetary gear set and with the output shaft through a secondinterconnecting member.

[0013] In accordance with a further aspect of the invention, a firstinput clutch selectively connects the input shaft with a member of thefirst or second planetary gear set that is not continuously connectedwith the output shaft.

[0014] In accordance with another aspect of the present invention, asecond input clutch selectively connects the input shaft with the secondmember of the third planetary gear set.

[0015] In another aspect of the invention, first, second and thirdtorque transmitting mechanisms, such as rotating synchronizers,selectively connect members of the first and second planetary gear setswith other members of the first and second planetary gear sets.

[0016] In still a further aspect of the invention, fourth and fifthtorque transmitting mechanisms, such as rotating synchronizers,selectively connect members of the third planetary gear set with membersof the fourth planetary gear set.

[0017] In still another aspect of the invention, sixth and seventhtorque transmitting mechanisms, such as braking synchronizers,selectively connect members of the first or second planetary gear set,that are not continuously connected with the output shaft or the firstinput clutch, with a stationary member (transmission housing).

[0018] In still another aspect of the invention, eighth and ninth torquetransmitting mechanisms, such as braking synchronizers, selectivelyconnect the second and third members of the fourth planetary gear setwith the stationary member.

[0019] In accordance with a further aspect of the invention, the inputclutches and torque transmitting mechanisms are selectively engaged incombinations of at least three to provide at least six forward speedratios and a reverse speed ratio.

[0020] In accordance with a further aspect of the invention, the firstinput clutch is applied for odd number speed ranges, and the secondinput clutch is applied for even number speed ranges, or vice versa.

[0021] In another aspect of the invention, the first input clutch andthe second input clutch are interchanged (i.e. alternately engaged) toshift from odd number speed range to even number speed range, or viceversa.

[0022] In accordance with a further aspect of the invention, eachselected torque transmitting mechanism for a new speed ratio is engagedprior to shifting of the input clutches to achieve shifts without torqueinterruptions.

[0023] In accordance with a further aspect of the invention, at leastone pair of synchronizers is executed as a double synchronizer to reducecost and package size.

[0024] In accordance with a further aspect of the invention, at leastone of the torque transmitting mechanisms can be eliminated to realizefive forward speed ratios and a reverse speed ratio.

[0025] The above objects, features, advantages, and other objects,features, and advantages of the present invention are readily apparentfrom the following detailed description of the best modes for carryingout the invention when taken in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1a is a schematic representation of a powertrain including aplanetary transmission incorporating a family member of the presentinvention;

[0027]FIG. 1b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 1a;

[0028]FIG. 2a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0029]FIG. 2b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 2a;

[0030]FIG. 3a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0031]FIG. 3b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 3a;

[0032]FIG. 4a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0033]FIG. 4b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 4a;

[0034]FIG. 5a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0035]FIG. 5b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 5a;

[0036]FIG. 6a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0037]FIG. 6b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 6a;

[0038]FIG. 7a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0039]FIG. 7b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 7a;

[0040]FIG. 8a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0041]FIG. 8b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 8a;

[0042]FIG. 9a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0043]FIG. 9b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 9a;

[0044]FIG. 10a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0045]FIG. 10b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 10a;

[0046]FIG. 11a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0047]FIG. 11b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 11a;

[0048]FIG. 12a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0049]FIG. 12b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 12a;

[0050]FIG. 13a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0051]FIG. 13b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 13a;

[0052]FIG. 14a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0053]FIG. 14b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 14a;

[0054]FIG. 15a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0055]FIG. 15b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 15a;

[0056]FIG. 16a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0057]FIG. 16b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 16a;

[0058]FIG. 17a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention; and

[0059]FIG. 17b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 17a.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0060] Referring to the drawings, wherein like characters represent thesame or corresponding parts throughout the several views, there is shownin FIG. 1a a powertrain 10 having a conventional engine 12, a planetarytransmission 14, and a conventional final drive mechanism 16.

[0061] The planetary transmission 14 includes an input shaft 17continuously connected with the engine 12, a planetary gear arrangement18, and an output shaft 19 continuously connected with the final drivemechanism 16. The planetary gear arrangement 18 includes four planetarygear sets 20, 30, 40 and 50.

[0062] The planetary gear set 20 includes a sun gear member 22, a ringgear member 24, and a planet carrier assembly member 26. The planetcarrier assembly member 26 includes a plurality of pinion gears 27rotatably mounted on a carrier member 29 and disposed in meshingrelationship with both the sun gear member 22 and the ring gear member24.

[0063] The planetary gear set 30 includes a sun gear member 32, a ringgear member 34, and a planet carrier assembly member 36. The planetcarrier assembly member 36 includes a plurality of intermeshing piniongears 37, 38 rotatably mounted on a carrier member 39 and disposed inmeshing relationship with the ring gear member 34 and the sun gearmember 32, respectively.

[0064] The planetary gear set 40 includes a sun gear member 42, a ringgear member 44, and a planet carrier assembly member 46. The planetcarrier assembly member 46 includes a plurality of pinion gears 47rotatably mounted on a carrier member 49 and disposed in meshingrelationship with both the sun gear member 42 and the ring gear member44.

[0065] The planetary gear set 50 includes a sun gear member 52, a ringgear member 54, and a planet carrier assembly member 56. The planetcarrier assembly member 56 includes a plurality of pinion gears 57rotatably mounted on a carrier member 59 and disposed in meshingrelationship with both the sun gear member 52 and the ring gear member54.

[0066] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 20, 30, 40 and 50 are divided into first andsecond transmission subsets 60, 61 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 60 includes planetary gear sets 20 and 30, andtransmission subset 61 includes planetary gear sets 40 and 50. Theoutput shaft 19 is continuously connected with members of both subsets60 and 61.

[0067] As mentioned above, the first and second input clutches 62, 63are alternatively engaged for transmitting power from the input shaft 17to transmission subset 60 or transmission subset 61. The first andsecond input clutches 62, 63 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 60, 61 prior to engaging therespective input clutches 62, 63. The preselection is achieved by meansof electronically controlled synchronizers. As shown, the planetary geararrangement includes nine torque transmitting mechanisms 64, 65, 66, 67,68, 69, 70, 71 and 72. The torque transmitting mechanisms 64, 65, 69 and70 comprise braking synchronizers, and the torque transmittingmechanisms 66, 67, 68, 71 and 72 comprise rotating synchronizers.

[0068] The rotating synchronizers and braking synchronizers arereferenced in the claims as follows: first, second and third torquetransmitting mechanisms 66, 67, 68; fourth and fifth torque transmittingmechanisms 71, 72; sixth and seventh torque transmitting mechanisms 64,65; and eighth and ninth torque transmitting mechanisms 69, 70. Otherfamily members are similarly referenced in the claims (i.e. rotatingsynchronizers of left, then right, transmission subset in Figures, thenbraking synchronizers of left, then right, transmission subset).

[0069] By way of example, synchronizers which may be implemented as therotating and/or braking synchronizers referenced herein are shown in thefollowing patents, each of which are incorporated by reference in theirentirety: U.S. Pat. Nos. 5,651,435; 5,975,263; 5,560,461; 5,641,045;5,497,867; 6,354,416.

[0070] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 60, 61 (i.e. through the clutch 62to the sun gear member 32 and through the clutch 63 to the sun gearmember 42). The sun gear member 22 is continuously connected with theplanet carrier assembly member 36 through the interconnecting member 74.The planet carrier assembly member 46 is continuously connected with thering gear member 24, the ring gear member 54 and the output shaft 19through the interconnecting member 76.

[0071] The sun gear member 22 is selectively connectable with thetransmission housing 80 through the braking synchronizer 64. The planetcarrier assembly member 26 is selectively connectable with thetransmission housing 80 through the braking synchronizer 65. The planetcarrier assembly member 26 is selectively connectable with the ring gearmember 34 through the rotating synchronizer 66. The ring gear member 24is selectively connectable with the ring gear member 34 through thebraking synchronizer 67. The ring gear member 34 is selectivelyconnectable with the sun gear member 32 through the rotatingsynchronizer 68. The planet carrier assembly member 56 is selectivelyconnectable with the transmission housing 80 through the brakingsynchronizer 69. The sun gear member 52 is selectively connectable withthe transmission housing 80 through the braking synchronizer 70. Thering gear member 44 is selectively connectable with the planet carrierassembly member 56 through the rotating synchronizer 71. The ring gearmember 44 is selectively connectable with the sun gear member 52 throughthe rotating synchronizer 72.

[0072] As shown in FIG. 1b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide seven forwardspeed ratios and a reverse speed ratio.

[0073] The reverse speed ratio is established with the engagement of theinput clutch 62, the braking synchronizer 65 and the rotatingsynchronizer 68. The input clutch 62 connects the sun gear member 32 tothe input shaft 17. The braking synchronizer 65 connects the planetcarrier assembly member 26 to the transmission housing 80. The rotatingsynchronizer 68 connects the ring gear member 34 to the sun gear member32. The sun gear member 22 and the planetary gear set 30 rotate at thesame speed as the input shaft 17. The planet carrier assembly member 26does not rotate. The ring gear member 24 and the planet carrier assemblymember 46 rotate at the same speed as the output shaft 19. The ring gearmember 24, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the sun gear member 22 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The numericalvalue of the reverse speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 20.

[0074] The first forward speed ratio is established with the engagementof the input clutch 63, the braking synchronizer 69 and the rotatingsynchronizer 72. The input clutch 63 connects the sun gear member 42 tothe input shaft 17. The braking synchronizer 69 connects the planetcarrier assembly member 56 to the transmission housing 80. The rotatingsynchronizer 72 connects the ring gear member 44 to the sun gear member52. The sun gear member 42 rotates at the same speed as the input shaft17. The planet carrier assembly member 46 and the ring gear member 54rotate at the same speed as the output shaft 19. The ring gear member 44rotates at the same speed as the sun gear member 52. The planet carrierassembly member 46, and therefore the output shaft 19, rotates at aspeed determined from the speed of the ring gear member 44, the speed ofthe sun gear member 42 and the ring gear/sun gear tooth ratio of theplanetary gear set 40. The planet carrier assembly member 56 does notrotate. The ring gear member 54 rotates at a speed determined from thespeed of the sun gear member 52 and the ring gear/sun gear tooth ratioof the planetary gear set 50. The numerical value of the first forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 40, 50.

[0075] The second forward speed ratio is established with the engagementof the input clutch 62, the braking synchronizer 65 and the rotatingsynchronizer 67. The input clutch 62 connects the sun gear member 32 tothe input shaft 17. The braking synchronizer 65 connects the planetcarrier assembly member 26 to the transmission housing 80. The rotatingsynchronizer 67 connects the ring gear member 24 to the ring gear member34. The sun gear member 22 rotates at the same speed as the planetcarrier assembly member 36. The planet carrier assembly member 26 doesnot rotate. The ring gear members 24, 34 and the planet carrier assemblymember 46 rotate at the same speed as the output shaft 19. The ring gearmember 24, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the sun gear member 22 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The sun gearmember 32 rotates at the same speed as the input shaft 17. The ring gearmember 34 rotates at a speed determined from the speed of the sun gearmember 32, the speed of the planet carrier assembly member 36 and thering gear/sun gear tooth ratio of the planetary gear set 30. Thenumerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear set20, 30.

[0076] The third forward speed ratio is established with the engagementof the input clutch 63, the braking synchronizer 69 and the rotatingsynchronizer 71. The input clutch 63 connects the sun gear member 42 tothe input shaft 17. The braking synchronizer 69 connects the planetcarrier assembly member 56 to the transmission housing 80. The rotatingsynchronizer 71 connects the ring gear member 44 to the planet carrierassembly member 56. The sun gear member 42 rotates at the same speed asthe input shaft 17. The planet carrier assembly member 46 and the ringgear member 54 rotate at the same speed as the output shaft 19. The ringgear member 44 and the planet carrier assembly member 56 do not rotate.The planet carrier assembly member 46, and therefore the output shaft19, rotates at a speed determined from the speed of the sun gear member42 and the ring gear/sun gear tooth ratio of the planetary gear set 40.The numerical value of the third forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set40.

[0077] The fourth forward speed ratio is established with the engagementof the input clutch 62, the braking synchronizer 65 and the rotatingsynchronizer 66. The input clutch 62 connects the sun gear member 32 tothe input shaft 17. The braking synchronizer 65 connects the planetcarrier assembly member 26 to the transmission housing 80. The rotatingsynchronizer 66 connects the planet carrier assembly member 26 to thering gear member 34. The sun gear member 22 rotates at the same speed asthe planet carrier assembly member 36. The planet carrier assemblymember 26 and the ring gear member 34 do not rotate. The ring gearmember 24 and the planet carrier assembly member 46 rotate at the samespeed as the output shaft 19. The ring gear member 24, and therefore theoutput shaft 19, rotates at a speed determined from the speed of the sungear member 22 and the ring gear/sun gear tooth ratio of the planetarygear set 20. The sun gear member 32 rotates at the same speed as theinput shaft 17. The planet carrier assembly member 36 rotates at a speeddetermined from the speed of the sun gear member 32 and the ringgear/sun gear tooth ratio of the planetary gear set 30. The numericalvalue of the fourth forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 20, 30.

[0078] The fifth forward speed ratio is established with the engagementof the input clutch 63, the braking synchronizer 70 and the rotatingsynchronizer 71. The input clutch 63 connects the sun gear member 42 tothe input shaft 17. The braking synchronizer 70 connects the sun gearmember 52 to the transmission housing 80. The rotating synchronizer 71connects the ring gear member 44 to the planet carrier assembly member56. The sun gear member 42 rotates at the same speed as the input shaft17. The planet carrier assembly member 46 and the ring gear member 54rotate at the same speed as the output shaft 19. The ring gear member 44rotates at the same speed as the planet carrier assembly member 56. Theplanet carrier assembly member 46, and therefore the output shaft 19,rotates at a speed determined from the speed of the ring gear member 44,the speed of the sun gear member 42 and the ring gear/sun gear toothratio of the planetary gear set 40. The sun gear member 52 does notrotate. The planet carrier assembly member 56 rotates at a speeddetermined from the speed of the ring gear member 54 and the ringgear/sun gear tooth ratio of the planetary gear set 50. The numericalvalue of the fifth forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear set 40, 50.

[0079] The sixth forward speed ratio is established with the engagementof the input clutch 62, the braking synchronizer 64 and the rotatingsynchronizer 66. The input clutch 62 connects the sun gear member 32 tothe input shaft 17. The braking synchronizer 64 connects the sun gearmember 22 to the transmission housing 80. The rotating synchronizer 66connects the planet carrier assembly member 26 to the ring gear member34. The sun gear member 22 and the planet carrier assembly member 36 donot rotate. The planet carrier assembly member 26 rotates at the samespeed as the ring gear member 34. The ring gear member 24 and the planetcarrier assembly member 46 rotate at the same speed as the output shaft19. The ring gear member 24, and therefore the output shaft 19, rotatesat a speed determined from the speed of the planet carrier assemblymember 26 and the ring gear/sun gear tooth ratio of the planetary gearset 20. The sun gear member 32 rotates at the same speed as the inputshaft 17. The ring gear member 34 rotates at a speed determined from thespeed of the sun gear member 32 and the ring gear/sun gear tooth ratioof the planetary gear set 30. The numerical value of the sixth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 20, 30.

[0080] The seventh forward speed ratio is established with theengagement of the input clutch 63 and the rotating synchronizers 71, 72.In this configuration, the input shaft 17 is directly connected to theoutput shaft 19. The numerical value of the seventh forward speed ratiois 1.

[0081] As set forth above, the engagement schedule for the torquetransmitting mechanisms is shown in the truth table of FIG. 1b. Thistruth table also provides an example of speed ratios that are availableutilizing the ring gear/sun gear tooth ratios given by way of example inFIG. 1b. The R1/S1 value is the tooth ratio of the planetary gear set20; the R2/S2 value is the tooth ratio of the planetary gear set 30; theR3/S3 value is the tooth ratio of the planetary gear set 40; and theR4/S4 value is the tooth ratio of the planetary gear set 50. Also, thechart of FIG. 1b describes the ratio steps that are attained utilizingthe sample of tooth ratios given. For example, the step ratio betweenfirst and second forward speed ratios is 1.65, while the step ratiobetween the reverse and first forward ratio is −0.43. Those skilled inthe art will recognize that since torque transmitting mechanisms 64 and65 are connected to a common member, transmission housing 80, and theyare not engaged at the same time for any of the speed ratios, the paircan be executed as a double synchronizer to reduce content and cost.Similarly, torque transmitting mechanisms pair 67 and 68 can be executedas a double synchronizer.

[0082]FIG. 2a shows a powertrain 110 having a conventional engine 12, aplanetary transmission 114, and a conventional final drive mechanism 16.The planetary transmission 114 includes an input shaft 17 connected withthe engine 12, a planetary gear arrangement 118, and an output shaft 19connected with the final drive mechanism 16. The planetary geararrangement 118 includes four planetary gear sets 120, 130, 140 and 150.

[0083] The planetary gear set 120 includes a sun gear member 122, a ringgear member 124, and a planet carrier assembly member 126. The planetcarrier assembly member 126 includes a plurality of pinion gears 127rotatably mounted on a carrier member 129 and disposed in meshingrelationship with both the sun gear member 122 and the ring gear member124.

[0084] The planetary gear set 130 includes a sun gear member 132, a ringgear member 134, and a planet carrier assembly member 136. The planetcarrier assembly member 136 includes a plurality of intermeshing piniongears 137, 138 rotatably mounted on a carrier member 139 and disposed inmeshing relationship with the ring gear member 134 and the sun gearmember 132, respectively.

[0085] The planetary gear set 140 includes a sun gear member 142, a ringgear member 144, and a planet carrier assembly member 146. The planetcarrier assembly member 146 includes a plurality of pinion gears 147rotatably mounted on a carrier member 149 and disposed in meshingrelationship with both the sun gear member 142 and the ring gear member144.

[0086] The planetary gear set 150 includes a sun gear member 152, a ringgear member 154, and a planet carrier assembly member 156. The planetcarrier assembly member 156 includes a plurality of pinion gears 157rotatably mounted on a carrier member 159 and disposed in meshingrelationship with both the sun gear member 152 and the ring gear member154.

[0087] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 120, 130, 140 and 150 are divided into firstand second transmission subsets 160, 161 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 160 includes planetary gear sets 120 and 130, andtransmission subset 161 includes planetary gear sets 140 and 150. Theoutput shaft 19 is continuously connected with members of both subsets160 and 161.

[0088] As mentioned above, the first and second input clutches 162, 163are alternatively engaged for transmitting power from the input shaft 17to transmission subset 160 or transmission subset 161. The first andsecond input clutches 162, 163 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 160, 161 prior to engagingthe respective input clutches 162, 163. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms164, 165, 166, 167, 168, 169, 170, 171 and 172. The torque transmittingmechanisms 164, 165, 169 and 170 comprise braking synchronizers, and thetorque transmitting mechanisms 166, 167, 168, 171 and 172 compriserotating synchronizers.

[0089] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 160, 161 (i.e. through the clutch162 to the sun gear member 122 and through the clutch 163 to the ringgear member 144). The planet carrier assembly member 126 is continuouslyconnected with the sun gear member 132 through the interconnectingmember 174. The planet carrier assembly member 146 is continuouslyconnected with the ring gear member 134 and the ring gear member 154through the interconnecting member 176.

[0090] The planet carrier assembly member 126 is selectively connectablewith the transmission housing 180 through the braking synchronizer 164.The ring gear member 124 is selectively connectable with thetransmission housing 180 through the braking synchronizer 165. The ringgear member 124 is selectively connectable with the planet carrierassembly member 136 through the rotating synchronizer 166. The sun gearmember 122 is selectively connectable with the planet carrier assemblymember 136 through the rotating synchronizer 167. The ring gear member134 is selectively connectable with the planet carrier assembly member136 through the rotating synchronizer 168. The planet carrier assemblymember 156 is selectively connectable with the transmission housing 180through the braking synchronizer 169. The sun gear member 152 isselectively connectable with the transmission housing 180 through thebraking synchronizer 170. The sun gear member 142 is selectivelyconnectable with the planet carrier assembly member 156 through therotating synchronizer 171. The sun gear member 142 is selectivelyconnectable with the sun gear member 152 through the rotatingsynchronizer 172.

[0091] As shown in FIG. 2b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide seven forwardspeed ratios and a reverse speed ratio.

[0092] The reverse speed ratio is established with the engagement of theinput clutch 162, the braking synchronizer 164 and the rotatingsynchronizer 166. The input clutch 162 connects the sun gear member 122to the input shaft 17. The braking synchronizer 164 connects the planetcarrier assembly member 126 to the transmission housing 180. Therotating synchronizer 166 connects the ring gear member 124 to theplanet carrier assembly member 136. The sun gear member 122 rotates atthe same speed as the input shaft 17. The planet carrier assembly member126 and the sun gear member 132 do not rotate. The ring gear member 124rotates at the same speed as the planet carrier assembly member 136. Thering gear member 124 rotates at a speed determined from the speed of thesun gear member 122 and the ring gear/sun gear tooth ratio of theplanetary gear set 120. The ring gear member 134 and the planet carrierassembly member 146 rotate at the same speed as the output shaft 19. Thering gear member 134, and therefore the output shaft 19, rotates at aspeed determined from the speed of the planet carrier assembly member136 and the ring gear/sun gear tooth ratio of the planetary gear set130. The numerical value of the reverse speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets120, 130.

[0093] The first forward speed ratio is established with the engagementof the input clutch 162, the braking synchronizer 165 and the rotatingsynchronizer 166. The input clutch 162 connects the sun gear member 122to the input shaft 17. The braking synchronizer 165 connects the ringgear member 124 to the transmission housing 180. The rotatingsynchronizer 166 connects the ring gear member 124 to the planet carrierassembly member 136. The sun gear member 122 rotates at the same speedas the input shaft 17. The planet carrier assembly member 126 rotates atthe same speed as the sun gear member 132. The ring gear member 124 andthe planet carrier assembly member 136 do not rotate. The planet carrierassembly member 126 rotates at a speed determined from the speed of thesun gear member 122 and the ring gear/sun gear tooth ratio of theplanetary gear set 120. The ring gear member 134 and the planet carrierassembly member 146 rotate at the same speed as the output shaft 19. Thering gear member 134, and therefore the output shaft 19, rotates at aspeed determined from the speed of the sun gear member 132 and the ringgear/sun gear tooth ratio of the planetary gear set 130. The numericalvalue of the first forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 120, 130.

[0094] The second forward speed ratio is established with the engagementof the input clutch 163, the braking synchronizer 169 and the rotatingsynchronizer 172. The input clutch 163 connects the ring gear member 144to the input shaft 17. The braking synchronizer 169 connects the planetcarrier assembly member 156 to the transmission housing 180. Therotating synchronizer 172 connects the sun gear member 142 to the sungear member 152. The sun gear member 142 rotates at the same speed asthe sun gear member 152. The planet carrier assembly member 146 and thering gear member 154 rotate at the same speed as the output shaft 19.The ring gear member 144 rotates at the same speed as the input shaft17. The planet carrier assembly member 146, and therefore the outputshaft 19, rotates at a speed determined from the speed of the ring gearmember 144, the speed of the sun gear member 142 and the ring gear/sungear tooth ratio of the planetary gear set 140. The planet carrierassembly member 156 does not rotate. The ring gear member 154 rotates ata speed determined from the speed of the sun gear member 152 and thering gear/sun gear tooth ratio of the planetary gear set 150. Thenumerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets140, 150.

[0095] The third forward speed ratio is established with the engagementof the input clutch 162, the braking synchronizer 165 and the rotatingsynchronizer 168. The input clutch 162 connects the sun gear member 122to the input shaft 17. The braking synchronizer 165 connects the ringgear member 124 to the transmission housing 180. The rotatingsynchronizer 168 connects the ring gear member 134 to the planet carrierassembly member 136. The sun gear member 122 rotates at the same speedas the input shaft 17. The planet carrier assembly member 126, theplanetary gear set 130 and the planet carrier assembly member 146rotates at the same speed as the output shaft 19. The ring gear member124 does not rotate. The planet carrier assembly member 126, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the sun gear member 122 and the ring gear/sun gear tooth ratioof the planetary gear set 120. The numerical value of the third forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 120.

[0096] The fourth forward speed ratio is established with the engagementof the input clutch 163, the braking synchronizer 169 and the rotatingsynchronizer 171. The input clutch 163 connects the ring gear member 144to the input shaft 17. The braking synchronizer 169 connects the planetcarrier assembly member 156 to the transmission housing 180. Therotating synchronizer 171 connects the sun gear member 142 to the planetcarrier assembly member 156. The sun gear member 142 and the planetcarrier assembly member 156 do not rotate. The planet carrier assemblymember 146 and the ring gear member 154 rotate at the same speed as theoutput shaft 19. The ring gear member 144 rotates at the same speed asthe input shaft 17. The planet carrier assembly member 146, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the ring gear member 144 and the ring gear/sun gear tooth ratioof the planetary gear set 140. The numerical value of the fourth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 140.

[0097] The fifth forward speed ratio is established with the engagementof the input clutch 162, the braking synchronizer 165 and the rotatingsynchronizer 167. The input clutch 162 connects the sun gear member 122to the input shaft 17. The braking synchronizer 165 connects the ringgear member 124 to the transmission housing 180. The rotatingsynchronizer 167 connects the sun gear member 122 to the planet carrierassembly member 136. The sun gear member 122 and the planet carrierassembly member 136 rotate at the same speed as the input shaft 17. Theplanet carrier assembly member 126 rotates at the same speed as the sungear member 132. The ring gear member 124 does not rotate. The planetcarrier assembly member 126 rotates at a speed determined from the speedof the sun gear member 122 and the ring gear/sun gear tooth ratio of theplanetary gear set 120. The ring gear member 134 and the planet carrierassembly member 146 rotate at the same speed as the output shaft 19. Thering gear member 134, and therefore the output shaft 19, rotates at aspeed determined from the speed of the planet carrier assembly member136, the speed of the sun gear member 132 and the ring gear/sun geartooth ratio of the planetary gear set 130. The numerical value of thefifth forward speed ratio is determined utilizing the ring gear/sun geartooth ratios of the planetary gear sets 120, 130.

[0098] The sixth forward speed ratio is established with the engagementof the input clutch 163, the braking synchronizer 170 and the rotatingsynchronizer 171. The input clutch 163 connects the ring gear member 144to the input shaft 17. The braking synchronizer 170 connects the sungear member 152 to the transmission housing 180. The rotatingsynchronizer 171 connects the sun gear member 142 to the planet carrierassembly member 156. The sun gear member 142 rotates at the same speedas the planet carrier assembly member 156. The planet carrier assemblymember 146 and the ring gear member 154 rotate at the same speed as theoutput shaft 19. The ring gear member 144 rotates at the same speed asthe input shaft 17. The planet carrier assembly member 146, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the ring gear member 144, the speed of the sun gear member 142and the ring gear/sun gear tooth ratio of the planetary gear set 140.The sun gear member 152 does not rotate. The planet carrier assemblymember 156 rotates at a speed determined from the speed of the ring gearmember 154 and the ring gear/sun gear tooth ratio of the planetary gearset 150. The numerical value of the sixth forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 140, 150.

[0099] The seventh forward speed ratio is established with theengagement of the input clutch 162 and the rotating synchronizers 167,168. In this configuration, the input shaft 17 is directly connected tothe output shaft 19. The numerical value of the seventh forward speedratio is 1.

[0100] As set forth above, the truth table of FIG. 2b describes theengagement sequence of the torque transmitting mechanisms utilized toprovide a reverse drive ratio and seven forward speed ratios. The truthtable also provides an example of the ratios that can be attained withthe family members shown in FIG. 2a utilizing the sample tooth ratiosgiven in FIG. 2b. The R1/S1 value is the tooth ratio of the planetarygear set 120; the R2/S2 value is the tooth ratio of the planetary gearset 130; the R3/S3 value is the tooth ratio of the planetary gear set140; and the R4/S4 value is the tooth ratio of the planetary gear set150. Also shown in FIG. 2b are the ratio steps between single stepratios in the forward direction as well as the reverse to first ratiostep. For example, the first to second step ratio is 1.77. Those skilledin the art will recognize that since torque transmitting mechanism 171and 172 are connected to a common member, sun gear member 142, and theyare not engaged at the same time for any of the gear ratios, the paircan be executed as a double synchronizer to reduce content and cost.Similarly, torque transmitting mechanisms pair 164 and 165 can beexecuted as a double synchronizer.

[0101] Turning the FIG. 3a, a powertrain 210 having a conventionalengine 12, a planetary transmission 214, and conventional final drivemechanism 16 is shown.

[0102] The planetary transmission 214 includes an input shaft 17continuously connected with the engine 12, a planetary gear arrangement218, and an output shaft 19 continuously connected with the final drivemechanism 16. The planetary gear arrangement 218 includes four planetarygear sets 220, 230, 240 and 250.

[0103] The planetary gear set 220 includes a sun gear member 222, a ringgear member 224, and a planet carrier assembly member 226. The planetcarrier assembly member 226 includes a plurality of pinion gears 227rotatably mounted on a carrier member 229 and disposed in meshingrelationship with both the sun gear member 222 and the ring gear member224.

[0104] The planetary gear set 230 includes a sun gear member 232, a ringgear member 234, and a planet carrier assembly member 236. The planetcarrier assembly member 236 includes a plurality of pinion gears 237rotatably mounted on a carrier member 239 and disposed in meshingrelationship with both the sun gear member 232 and the ring gear member234.

[0105] The planetary gear set 240 includes a sun gear member 242, a ringgear member 244, and a planet carrier assembly member 246. The planetcarrier assembly member 246 includes a plurality of pinion gears 247rotatably mounted on a carrier member 249 and disposed in meshingrelationship with both the sun gear member 242 and the ring gear member244.

[0106] The planetary gear set 250 includes a sun gear member 252, a ringgear member 254, and a planet carrier assembly member 256. The planetcarrier assembly member 256 includes a plurality of intermeshing piniongears 257, 258 rotatably mounted on a carrier member 259 and disposed inmeshing relationship with the ring gear member 254 and the sun gearmember 252, respectively.

[0107] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 220, 230, 240 and 250 are divided into firstand second transmission subsets 260, 261 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 260 includes planetary gear sets 220 and 230, andtransmission subset 261 includes planetary gear sets 240 and 250. Theoutput shaft 19 is continuously connected with members of both subsets260 and 261.

[0108] As mentioned above, the first and second input clutches 262, 263are alternatively engaged for transmitting power from the input shaft 17to transmission subset 260 or transmission subset 261. The first andsecond input clutches 262, 263 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 260, 261 prior to engagingthe respective input clutches 262, 263. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms264, 265, 266, 267, 268, 269, 270, 271 and 272. The torque transmittingmechanisms 264, 265, 269 and 270 comprise braking synchronizers, and thetorque transmitting mechanisms 266, 267, 268, 271 and 272 compriserotating synchronizers.

[0109] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 260, 261 (i.e. through the clutch262 to the sun gear member 222 and through the clutch 263 to the sungear member 242). The ring gear member 224 is continuously connectedwith the sun gear member 232 through the interconnecting member 274. Theplanet carrier assembly member 246 is continuously connected with thering gear members 234, 254 and the output shaft 19 through theinterconnecting member 276.

[0110] The ring gear member 224 is selectively connectable with thetransmission housing 280 through the braking synchronizer 264. Theplanet carrier assembly member 236 is selectively connectable with thetransmission housing 280 through the braking synchronizer 265. Theplanet carrier assembly member 226 is selectively connectable with theplanet carrier assembly member 236 through the rotating synchronizer266. The ring gear member 224 is selectively connectable with the planetcarrier assembly member 226 through the rotating synchronizer 267. Thesun gear member 222 is selectively connectable with the planet carrierassembly member 236 through the rotating synchronizer 268. The planetcarrier assembly member 256 is selectively connectable with thetransmission housing 280 through the braking synchronizer 269. The sungear member 252 is selectively connectable with the transmission housing280 through the braking synchronizer 270. The ring gear member 244 isselectively connectable with the planet carrier assembly member 256through the rotating synchronizer 271. The ring gear member 244 isselectively connectable with the sun gear member 252 through therotating synchronizer 272.

[0111] As shown in FIG. 3b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

[0112] The reverse speed ratio is established with the engagement of theinput clutch 262, the braking synchronizer 265 and the rotatingsynchronizer 267. The input clutch 262 connects the sun gear member 222to the input shaft 17. The braking synchronizer 265 connects the planetcarrier assembly member 236 to the transmission housing 280. Therotating synchronizer 267 connects the ring gear member 224 to theplanet carrier assembly member 226. The planetary gear set 220 and thesun gear member 232 rotates at the same speed as the input shaft 17. Theplanet carrier assembly member 236 does not rotate. The ring gear member234 and the planet carrier assembly member 246 rotate at the same speedas the output shaft 19. The ring gear member 234, and therefore theoutput shaft 19, rotates at a speed determined from the speed of the sungear member 232 and the ring gear/sun gear tooth ratio of the planetarygear set 230. The numerical value of the reverse speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 230.

[0113] The first forward speed ratio is established with the engagementof the input clutch 262, the braking synchronizer 265 and the rotatingsynchronizer 266. The input clutch 262 connects the sun gear member 222to the input shaft 17. The braking synchronizer 265 connects the planetcarrier assembly member 236 to the transmission housing 280. Therotating synchronizer 266 connects the planet carrier assembly member226 to the planet carrier assembly member 236. The sun gear member 222rotates at the same speed as the input shaft 17. The planet carrierassembly member 226 and the planet carrier assembly member 236 do notrotate. The ring gear member 224 rotates at the same speed as the sungear member 232. The ring gear member 224 rotates at a speed determinedfrom the speed of the sun gear member 222 and the ring gear/sun geartooth ratio of the planetary gear set 220. The ring gear member 234 andthe planet carrier assembly member 246 rotate at the same speed as theoutput shaft 19. The ring gear member 234, and therefore the outputshaft 19, rotates at a speed determined from the speed of the sun gearmember 232 and the ring gear/sun gear tooth ratio of the planetary gearset 230. The numerical value of the first forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 220, 230.

[0114] The second forward speed ratio is established with the engagementof the input clutch 263, the braking synchronizer 269 and the rotatingsynchronizer 271. The input clutch 263 connects the sun gear member 242to the input shaft 17. The braking synchronizer 269 connects the planetcarrier assembly member 256 to the transmission housing 280. Therotating synchronizer 271 connects the ring gear member 244 to theplanet carrier assembly member 256. The sun gear member 242 rotates atthe same speed as the input shaft 17. The planet carrier assembly member246 and the ring gear member 254 rotate at the same speed as the outputshaft 19. The ring gear member 244 and the planet carrier assemblymember 256 do not rotate. The planet carrier assembly member 246, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the sun gear member 242 and the ring gear/sun gear tooth ratioof the planetary gear set 240. The numerical value of the second forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 240.

[0115] The third forward speed ratio is established with the engagementof the input clutch 262 and the rotating synchronizers 266, 268. In thisconfiguration, the input shaft 17 is directly connected to the outputshaft 19. The numerical value of the third forward speed ratio is 1.

[0116] The fourth forward speed ratio is established with the engagementof the input clutch 263, the braking synchronizer 270 and the rotatingsynchronizer 271. The input clutch 263 connects the sun gear member 242to the input shaft 17. The braking synchronizer 270 connects the sungear member 252 to the transmission housing 280. The rotatingsynchronizer 271 connects the ring gear member 244 to the planet carrierassembly member 256. The sun gear member 242 rotates at the same speedas the input shaft 17. The planet carrier assembly member 246 and thering gear member 254 rotate at the same speed as the output shaft 19.The ring gear member 244 rotates at the same speed as the planet carrierassembly member 256. The planet carrier assembly member 246, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the ring gear member 244, the speed of the sun gear member 242and the ring gear/sun gear tooth ratio of the planetary gear set 240.The sun gear member 252 does not rotate. The planet carrier assemblymember 256 rotates at a speed determined from the speed of the ring gearmember 254 and the ring gear/sun gear tooth ratio of the planetary gearset 250. The numerical value of the fourth forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 240, 250.

[0117] The fifth forward speed ratio is established with the engagementof the input clutch 262, the braking synchronizer 264 and the rotatingsynchronizer 268. The input clutch 262 connects the sun gear member 222to the input shaft 17. The braking synchronizer 264 connects the ringgear member 224 to the transmission housing 280. The rotatingsynchronizer 268 connects the sun gear member 222 to the planet carrierassembly member 236. The sun gear member 222 and the planet carrierassembly member 236 rotate at the same speed as the input shaft 17. Thering gear member 224 and the sun gear member 232 do not rotate. The ringgear member 234 and the planet carrier assembly member 246 rotate at thesame speed as the output shaft 19. The ring gear member 234, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the planet carrier assembly member 236 and the ring gear/sungear tooth ratio of the planetary gear set 230. The numerical value ofthe fifth forward speed ratio is determined utilizing the ring gear/sungear tooth ratio of the planetary gear set 230.

[0118] The sixth forward speed ratio is established with the engagementof the input clutch 263, the braking synchronizer 269 and the rotatingsynchronizer 272. The input clutch 263 connects the sun gear member 242to the input shaft 17. The braking synchronizer 269 connects the planetcarrier assembly member 256 to the transmission housing 280. Therotating synchronizer 272 connects the ring gear member 244 to the sungear member 252. The sun gear member 242 rotates at the same speed asthe input shaft 17. The planet carrier assembly member 246 and the ringgear member 254 rotate at the same speed as the output shaft 19. Thering gear member 244 rotates at the same speed as the sun gear member252. The planet carrier assembly member 246, and therefore the outputshaft 19, rotates at a speed determined from the speed of the ring gearmember 244, the speed of the sun gear member 242 and the ring gear/sungear tooth ratio of the planetary gear set 240. The planet carrierassembly member 256 does not rotate. The ring gear member 254 rotates ata speed determined from the speed of the sun gear member 252 and thering gear/sun gear tooth ratio of the planetary gear set 250. Thenumerical value of the sixth forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 240, 250.

[0119] As previously set forth, the truth table of FIG. 3b describes thecombinations of engagements utilized for six forward speed ratios andone reverse speed ratio. The truth table also provides an example ofspeed ratios that are available with the family member described above.These examples of speed ratios are determined the tooth ratios given inFIG. 3b. The R1/S1 value is the tooth ratio of the planetary gear set220; the R2/S2 value is the tooth ratio of the planetary gear set 230;the R3/S3 value is the tooth ratio of the planetary gear set 240; andthe R4/S4 value is the tooth ratio of the planetary gear set 250. Alsodepicted in FIG. 3b is a chart representing the ratio steps betweenadjacent forward speed ratios and the reverse speed ratio. For example,the first to second ratio interchange has a step of 1.86.

[0120] A powertrain 310, shown in FIG. 4a, includes the engine 12, aplanetary transmission 314, and the final drive mechanism 16. Theplanetary transmission 314 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 318, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 318 includes four planetary gear sets320, 330, 340 and 350.

[0121] The planetary gear set 320 includes a sun gear member 322, a ringgear member 324, and a planet carrier assembly member 326. The planetcarrier assembly member 326 includes a plurality of intermeshing piniongears 327, 328 rotatably mounted on a carrier member 329 and disposed inmeshing relationship with the ring gear member 324 and the sun gearmember 322, respectively.

[0122] The planetary gear set 330 includes a sun gear member 332, a ringgear member 334, and a planet carrier assembly member 336. The planetcarrier assembly member 336 includes a plurality of pinion gears 337rotatably mounted on a carrier member 339 and disposed in meshingrelationship with both the sun gear member 332 and the ring gear member334.

[0123] The planetary gear set 340 includes a sun gear member 342, a ringgear member 344, and a planet carrier assembly member 346. The planetcarrier assembly member 346 includes a plurality of pinion gears 347rotatably mounted on a carrier member 349 and disposed in meshingrelationship with both the sun gear member 342 and the ring gear member344.

[0124] The planetary gear set 350 includes a sun gear member 352, a ringgear member 354, and a planet carrier assembly member 356. The planetcarrier assembly member 356 includes a plurality of pinion gears 357rotatably mounted on a carrier member 359 and disposed in meshingrelationship with both the sun gear member 352 and the ring gear member354.

[0125] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 320, 330, 340 and 350 are divided into firstand second transmission subsets 360, 361 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 360 includes planetary gear sets 320 and 330, andtransmission subset 361 includes planetary gear sets 340 and 350. Theoutput shaft 19 is continuously connected with members of both subsets360 and 361.

[0126] As mentioned above, the first and second input clutches 362, 363are alternatively engaged for transmitting power from the input shaft 17to transmission subset 360 or transmission subset 361. The first andsecond input clutches 362, 363 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 360, 361 prior to engagingthe respective input clutches 362, 363. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms364, 365, 366, 367, 368, 369, 370, 371 and 372. The torque transmittingmechanisms 364, 365, 369 and 370 comprise braking synchronizers, and thetorque transmitting mechanisms 366, 367, 368, 371 and 372 compriserotating synchronizers.

[0127] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 360, 361 (i.e. through the clutch362 to the sun gear member 332 and through the clutch 363 to the sungear member 342). The sun gear member 322 is continuously connected withthe planet carrier assembly member 336 through the interconnectingmember 374. The planet carrier assembly member 346 is continuouslyconnected with the ring gear members 324, 354 and the output shaft 19through the interconnecting member 376.

[0128] The sun gear member 322 is selectively connectable with thetransmission housing 380 through the braking synchronizer 364. Theplanet carrier assembly member 326 is selectively connectable with thetransmission housing 380 through the braking synchronizer 365. Theplanet carrier assembly member 326 is selectively connectable with thering gear member 334 through the rotating synchronizer 366. The ringgear member 324 is selectively connectable with the ring gear member 334through the rotating synchronizer 367. The ring gear member 334 isselectively connectable with the sun gear member 332 through therotating synchronizer 368. The planet carrier assembly member 356 isselectively connectable with the transmission housing 380 through thebraking synchronizer 369. The sun gear member 352 is selectivelyconnectable with the transmission housing 380 through the brakingsynchronizer 370. The ring gear member 344 is selectively connectablewith the planet carrier assembly member 356 through the rotatingsynchronizer 371. The ring gear member 344 is selectively connectablewith the sun gear member 352 through the rotating synchronizer 372.

[0129] The truth tables given in FIGS. 4b, 5 b, 6 b, 7 b, 8 b, 9 b, 10b, 11 b, 12 b, 13 b, 14 b, 15 b and 16 b show the engagement sequencesfor the torque transmitting mechanisms to provide at least five forwardspeed ratios and one reverse speed ratio. As shown and described abovefor the configurations in FIGS. 1a, 2 a and 3 a, those skilled in theart will understand from the respective truth tables how the speedratios are established through the planetary gear sets identified in thewritten description.

[0130] The truth table shown in FIG. 4b describes the engagementcombination and engagement sequence necessary to provide the reversedrive ratio and seven forward speed ratios. A sample of the numericalvalues for the ratios is also provided in the truth table of FIG. 4b.These values are determined utilizing the ring gear/sun gear toothratios also given in FIG. 4b. The R1/S1 value is the tooth ratio for theplanetary gear set 320; the R2/S2 value is the tooth ratio for theplanetary gear set 330; the R3/S3 value is the tooth ratio for theplanetary gear set 340; and the R4/S4 value is the tooth ratio for theplanetary gear set 350. Also given in FIG. 4b is a chart describing thestep ratios between the adjacent forward speed ratios and the reverse tofirst forward speed ratio. For example, the first to second forwardspeed ratio step is 1.69.

[0131] Those skilled in the art will recognize that the numerical valuesof the reverse, second and fourth forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets320, 330. The numerical values of the first and fifth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 340, 350. The numerical value of the thirdforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 340. The numerical value of the sixthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 320. The numerical value of the seventhforward speed ratio is 1.

[0132] A powertrain 410 shown in FIG. 5a includes a conventional engine12, a planetary transmission 414, and a conventional final drivemechanism 16. The planetary transmission 414 includes an input shaft 17connected with the engine 12, a planetary gear arrangement 418, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 418 includes four planetary gear sets420, 430, 440 and 450.

[0133] The planetary gear set 420 includes a sun gear member 422, a ringgear member 424, and a planet carrier assembly member 426. The planetcarrier assembly member 426 includes a plurality of pinion gears 427rotatably mounted on a carrier member 429 and disposed in meshingrelationship with both the sun gear member 422 and the ring gear member424.

[0134] The planetary gear set 430 includes a sun gear member 432, a ringgear member 434, and a planet carrier assembly member 436. The planetcarrier assembly member 436 includes a plurality of intermeshing piniongears 437, 438 rotatably mounted on a carrier member 439 and disposed inmeshing relationship with the ring gear member 434 and the sun gearmember 432, respectively.

[0135] The planetary gear set 440 includes a sun gear member 442, a ringgear member 444, and a planet carrier assembly member 446. The planetcarrier assembly member 446 includes a plurality of pinion gears 447rotatably mounted on a carrier member 449 and disposed in meshingrelationship with both the sun gear member 442 and the ring gear member444.

[0136] The planetary gear set 450 includes a sun gear member 452, a ringgear member 454, and a planet carrier assembly member 456. The planetcarrier assembly member 456 includes a plurality of pinion gears 457rotatably mounted on a carrier member 459 and disposed in meshingrelationship with both the sun gear member 452 and the ring gear member454.

[0137] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 420, 430, 440 and 450 are divided into firstand second transmission subsets 460, 461 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 460 includes planetary gear sets 420 and 430, andtransmission subset 461 includes planetary gear sets 440 and 450. Theoutput shaft 19 is continuously connected with members of both subsets460 and 461.

[0138] As mentioned above, the first and second input clutches 462, 463are alternatively engaged for transmitting power from the input shaft 17to transmission subset 460 or transmission subset 461. The first andsecond input clutches 462, 463 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 460, 461 prior to engagingthe respective input clutches 462, 463. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms464, 465, 466, 467, 468, 469, 470, 471 and 472. The torque transmittingmechanisms 464, 465, 469 and 470 comprise braking synchronizers, and thetorque transmitting mechanisms 466, 467, 468, 471 and 472 compriserotating synchronizers.

[0139] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 460, 461 (i.e. through the clutch462 to the sun gear member 422 and through the clutch 463 to the sungear member 442). The planet carrier assembly member 426 is continuouslyconnected with the sun gear member 432 through the interconnectingmember 474. The planet carrier assembly member 446 is continuouslyconnected with the ring gear members 434, 454 and the output shaft 19through the interconnecting member 476.

[0140] The planet carrier assembly member 426 is selectively connectablewith the transmission housing 480 through the braking synchronizer 464.The planet carrier assembly member 436 is selectively connectable withthe transmission housing 480 through the braking synchronizer 465. Thering gear member 424 is selectively connectable with the planet carrierassembly member 436 through the rotating synchronizer 466. The ring gearmember 424 is selectively connectable with the planet carrier assemblymember 426 through the rotating synchronizer 467. The sun gear member422 is selectively connectable with the planet carrier assembly member436 through the rotating synchronizer 468. The planet carrier assemblymember 456 is selectively connectable with the transmission housing 480through the braking synchronizer 469. The sun gear member 452 isselectively connectable with the transmission housing 480 through thebraking synchronizer 470. The ring gear member 444 is selectivelyconnectable with the planet carrier assembly member 456 through therotating synchronizer 471. The ring gear member 444 is selectivelyconnectable with the sun gear member 452 through the rotatingsynchronizer 472.

[0141] As shown in FIG. 5b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide seven forwardspeed ratios and a reverse speed ratio.

[0142]FIG. 5b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first ratio. For example, theratio step between the first and second forward ratios is 1.57. Thoseskilled in the art will recognize that the numerical values of thereverse, second and sixth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 420, 430.The numerical values of the first and fifth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 440, 450. The numerical value of the third forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 440. The numerical value of the fourth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 430. The numerical value of seventh forwardspeed ratio is 1.

[0143] A powertrain 510, shown in FIG. 6a, includes a conventionalengine 12, a powertrain 514, and a conventional final drive mechanism16. The powertrain 514 includes an input shaft 17 connected with theengine 12, a planetary gear arrangement 518, and an output shaft 19continuously connected with the final drive mechanism 16. The planetarygear arrangement 518 includes four planetary gear sets 520, 530, 540 and550.

[0144] The planetary gear set 520 includes a sun gear member 522, a ringgear member 524, and a planet carrier assembly member 526. The planetcarrier assembly member 526 includes a plurality of pinion gears 527rotatably mounted on a carrier member 529 and disposed in meshingrelationship with both the sun gear member 522 and the ring gear member524.

[0145] The planetary gear set 530 includes a sun gear member 532, a ringgear member 534, and a planet carrier assembly member 536. The planetcarrier assembly member 536 includes a plurality of pinion gears 537rotatably mounted on a carrier member 539 and disposed in meshingrelationship with both the sun gear member 532 and the ring gear member534.

[0146] The planetary gear set 540 includes a sun gear member 542, a ringgear member 544, and a planet carrier assembly member 546. The planetcarrier assembly member 546 includes a plurality of pinion gears 547rotatably mounted on a carrier member 549 and disposed in meshingrelationship with both the sun gear member 542 and the ring gear member544.

[0147] The planetary gear set 550 includes a sun gear member 552, a ringgear member 554, and a planet carrier assembly member 556. The planetcarrier assembly member 556 includes a plurality of intermeshing piniongears 557, 558 rotatably mounted on a carrier member 559 and disposed inmeshing relationship with the ring gear member 554 and the sun gearmember 552, respectively.

[0148] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 520, 530, 540 and 550 are divided into firstand second transmission subsets 560, 561 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 560 includes planetary gear sets 520 and 530, andtransmission subset 561 includes planetary gear sets 540 and 550. Theoutput shaft 19 is continuously connected with members of both subsets560 and 561.

[0149] As mentioned above, the first and second input clutches 562, 563are alternatively engaged for transmitting power from the input shaft 17to transmission subset 560 or transmission subset 561. The first andsecond input clutches 562, 563 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 560, 561 prior to engagingthe respective input clutches 562, 563. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms564, 565, 566, 567, 568, 569, 570, 571 and 572. The torque transmittingmechanisms 564, 565, 569 and 570 comprise braking synchronizers, and thetorque transmitting mechanisms 566, 567, 568, 571 and 572 compriserotating synchronizers.

[0150] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 560, 561 (i.e. through the clutch562 to the sun gear member 532 and through the clutch 563 to the sungear member 542). The planet carrier assembly member 526 is continuouslyconnected with the ring gear member 534 through the interconnectingmember 574. The planet carrier assembly member 546 is continuouslyconnected with the ring gear member 524, the sun gear member 552 and theoutput shaft 19 through the interconnecting member 576.

[0151] The planet carrier assembly member 526 is selectively connectablewith the transmission housing 580 through the braking synchronizer 564.The sun gear member 522 is selectively connectable with the transmissionhousing 580 through the braking synchronizer 565. The planet carrierassembly member 536 is selectively connectable with the sun gear member532 through the rotating synchronizer 566. The ring gear member 524 isselectively connectable with the planet carrier assembly member 536through the rotating synchronizer 567. The sun gear member 522 isselectively connectable with the sun gear member 532 through therotating synchronizer 568. The ring gear member 554 is selectivelyconnectable with the transmission housing 580 through the brakingsynchronizer 569. The planet carrier assembly member 556 is selectivelyconnectable with the transmission housing 580 through the brakingsynchronizer 570. The ring gear member 544 is selectively connectablewith the ring gear member 554 through the rotating synchronizer 571. Thering gear member 544 is selectively connectable with the planet carrierassembly member 556 through the rotating synchronizer 572.

[0152] As shown in FIG. 6b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The chart of FIG. 6b describesthe ratio steps between adjacent forward speed ratios and the ratio stepbetween the reverse and first forward speed ratio.

[0153] Those skilled in the art, upon reviewing the truth table and theschematic representation of FIG. 6a can determine that the numericalvalues of the reverse and sixth forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set520. The numerical values of the first and third forward speed ratiosare determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 540, 550. The numerical value of the second forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 530. The numerical value of the fourth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 520, 530. The numerical value of the fifthforward speed ratio is 1.

[0154] The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 6b. R1/S1 value isthe tooth ratio of the planetary gear set 520; the R2/S2 value is thetooth ratio of the planetary gear set 530; the R3/S3 value is the toothratio of the planetary gear set 540; and the R4/S4 value is the toothratio of the planetary gear set 550.

[0155] A powertrain 610, shown in FIG. 7a, has the engine and torqueconverter 12, a planetary transmission 614, and the final drivemechanism 16. The planetary transmission 614 includes the input shaft17, a planetary gear arrangement 618, and the output shaft 19. Theplanetary gear arrangement 618 includes four planetary gear sets 620,630, 640 and 650.

[0156] The planetary gear set 620 includes a sun gear member 622, a ringgear member 624, and a planet carrier assembly member 626. The planetcarrier assembly member 626 includes a plurality of pinion gears 627rotatably mounted on a carrier member 629 and disposed in meshingrelationship with both the sun gear member 622 and the ring gear member624.

[0157] The planetary gear set 630 includes a sun gear member 632, a ringgear member 634, and a planet carrier assembly member 636. The planetcarrier assembly member 636 includes a plurality of intermeshing piniongears 637, 638 rotatably mounted on a carrier member 639 and disposed inmeshing relationship with the ring gear member 634 and the sun gearmember 632, respectively.

[0158] The planetary gear set 640 includes a sun gear member 642, a ringgear member 644, and a planet carrier assembly member 646. The planetcarrier assembly member 646 includes a plurality of pinion gears 647rotatably mounted on a carrier member 649 and disposed in meshingrelationship with both the sun gear member 642 and the ring gear member644.

[0159] The planetary gear set 650 includes a sun gear member 652, a ringgear member 654, and a planet carrier assembly member 656. The planetcarrier assembly member 656 includes a plurality of intermeshing piniongears 657, 658 rotatably mounted on a carrier member 659 and disposed inmeshing relationship with the ring gear member 654 and the sun gearmember 652, respectively.

[0160] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 620, 630, 640 and 650 are divided into firstand second transmission subsets 660, 661 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 660 includes planetary gear sets 620 and 630, andtransmission subset 661 includes planetary gear sets 640 and 650. Theoutput shaft 19 is continuously connected with members of both subsets660 and 661.

[0161] As mentioned above, the first and second input clutches 662, 663are alternatively engaged for transmitting power from the input shaft 17to transmission subset 660 or transmission subset 661. The first andsecond input clutches 662, 663 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 660, 661 prior to engagingthe respective input clutches 662, 663. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms664, 665, 666, 667, 668, 669, 670, 671 and 672. The torque transmittingmechanisms 664, 665, 669 and 670 comprise braking synchronizers, and thetorque transmitting mechanisms 666, 667, 668, 671 and 672 compriserotating synchronizers.

[0162] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 660, 661 (i.e. through the clutch662 to the sun gear member 632 and through the clutch 663 to the sungear member 642). The sun gear member 622 is continuously connected withthe planet carrier assembly member 636 through the interconnectingmember 674. The planet carrier assembly member 646 is continuouslyconnected with the ring gear member 624, the sun gear member 652 and theoutput shaft 19 through the interconnecting member 676.

[0163] The sun gear member 622 is selectively connectable with thetransmission housing 680 through the braking synchronizer 664. Theplanet carrier assembly member 626 is selectively connectable with thetransmission housing 680 through the braking synchronizer 665. Theplanet carrier assembly member 626 is selectively connectable with thering gear member 634 through the rotating synchronizer 666. The ringgear member 624 is selectively connectable with the ring gear member 634through the rotating synchronizer 667. The ring gear member 634 isselectively connectable with the sun gear member 632 through therotating synchronizer 668. The ring gear member 654 is selectivelyconnectable with the transmission housing 680 through the brakingsynchronizer 669. The planet carrier assembly member 656 is selectivelyconnectable with the transmission housing 680 through the brakingsynchronizer 670. The ring gear member 644 is selectively connectablewith the ring gear member 654 through the rotating synchronizer 671. Thering gear member 644 is selectively connectable with the planet carrierassembly member 656 through the rotating synchronizer 672.

[0164] As shown in FIG. 7b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide seven forwardspeed ratios and a reverse speed ratio. The ratio values given are byway example and are established utilizing the ring gear/sun gear toothratios given in FIG. 7b. For example, the R1/S2 value is the tooth ratioof the planetary gear set 620; the R2/S2 value is the tooth ratio of theplanetary gear set 630; the R3/S3 value is the tooth ratio of theplanetary gear set 640; and the R4/S4 value is the tooth ratio of theplanetary gear set 650. The ratio steps between adjacent forward ratiosand the reverse to first ratio are also given in FIG. 7b.

[0165] Those skilled in the art will, upon reviewing the truth table ofFIG. 7b, recognize that the numerical value reverse speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 620. The numerical values of the first and fifth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 640, 650. The numerical values of the second,fourth and sixth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratios of the planetary gear set 620, 630. Thenumerical value of the seventh forward speed ratio is 1.

[0166] A powertrain 710, shown in FIG. 8a, has the conventional engine12, a planetary transmission 714, and the conventional final drivemechanism 16. The engine 12 is continuously connected with the inputshaft 17. The planetary transmission 714 is drivingly connected with thefinal drive mechanism 16 through the output shaft 19. The planetarytransmission 714 includes a planetary gear arrangement 718 that has afirst planetary gear set 720, a second planetary gear set 730, a thirdplanetary gear set 740, and a fourth planetary gear set 750.

[0167] The planetary gear set 720 includes a sun gear member 722, a ringgear member 724, and a planet carrier assembly member 726. The planetcarrier assembly member 726 includes a plurality of pinion gears 727rotatably mounted on a carrier member 729 and disposed in meshingrelationship with both the sun gear member 722 and the ring gear member724.

[0168] The planetary gear set 730 includes a sun gear member 732, a ringgear member 734, and a planet carrier assembly member 736. The planetcarrier assembly member 736 includes a plurality of intermeshing piniongears 737, 738 rotatably mounted on a carrier member 739 and disposed inmeshing relationship with the ring gear member 734 and the sun gearmember 732, respectively.

[0169] The planetary gear set 740 includes a sun gear member 742, a ringgear member 744, and a planet carrier assembly member 746. The planetcarrier assembly member 746 includes a plurality of pinion gears 747rotatably mounted on a carrier member 749 and disposed in meshingrelationship with both the sun gear member 742 and the ring gear member744.

[0170] The planetary gear set 750 includes a sun gear member 752, a ringgear member 754, and a planet carrier assembly member 756. The planetcarrier assembly member 756 includes a plurality of pinion gears 757rotatably mounted on a carrier member 759 and disposed in meshingrelationship with both the sun gear member 752 and the ring gear member754.

[0171] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 720, 730, 740 and 750 are divided into firstand second transmission subsets 760, 761 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 760 includes planetary gear sets 720 and 730, andtransmission subset 761 includes planetary gear sets 740 and 750. Theoutput shaft 19 is continuously connected with members of both subsets760 and 761.

[0172] As mentioned above, the first and second input clutches 762, 763are alternatively engaged for transmitting power from the input shaft 17to transmission subset 760 or transmission subset 761. The first andsecond input clutches 762, 763 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 760, 761 prior to engagingthe respective input clutches 762, 763. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms764, 765, 766, 767, 768, 769, 770, 771 and 772. The torque transmittingmechanisms 764, 765, 769 and 770 comprise braking synchronizers, and thetorque transmitting mechanisms 766, 767, 768, 771 and 772 compriserotating synchronizers.

[0173] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 760, 761 (i.e. through the clutch762 to the sun gear member 722 and through the clutch 763 to the sungear member 742). The planet carrier assembly member 726 is continuouslyconnected with the sun gear member 732 through the interconnectingmember 774. The planet carrier assembly member 746 is continuouslyconnected with the ring gear members 734, 754 and the output shaft 19through the interconnecting member 776.

[0174] The planet carrier assembly member 726 is selectively connectablewith the transmission housing 780 through the braking synchronizer 764.The ring gear member 724 is selectively connectable with thetransmission housing 780 through the braking synchronizer 765. The ringgear member 724 is selectively connectable with the planet carrierassembly member 736 through the rotating synchronizer 766. The sun gearmember 722 is selectively connectable with the planet carrier assemblymember 736 through the rotating synchronizer 767. The ring gear member734 is selectively connectable with the planet carrier assembly member736 through the rotating synchronizer 768. The planet carrier assemblymember 756 is selectively connectable with the transmission housing 780through the braking synchronizer 769. The sun gear member 752 isselectively connectable with the transmission housing 780 through thebraking synchronizer 770. The ring gear member 744 is selectivelyconnectable with the planet carrier assembly member 756 through therotating synchronizer 771. The ring gear member 744 is selectivelyconnectable with the sun gear member 752 through the rotatingsynchronizer 772.

[0175] As shown in FIG. 8b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide seven forwardspeed ratios and a reverse speed ratio. Also given in the truth table isa set of numerical values that are attainable with the present inventionutilizing the ring gear/sun gear tooth ratios given in FIG. 8b. TheR1/S1 value is the tooth ratio of the planetary gear set 720; the R2/S2value is the tooth ratio of the planetary gear set 730; the R3/S3 valueis the tooth ratio of the planetary gear set 740; and the R4/S4 value isthe tooth ratio of the planetary gear set 750.

[0176]FIG. 8b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is1.50.

[0177] Those skilled in the art will recognize that the numerical valuesof the reverse, second and sixth forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets720, 730. The numerical values of the first and fifth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 740, 750. The numerical value of the thirdforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 740. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 720. The numerical value of the seventhforward speed ratio is 1.

[0178] A powertrain 810, shown in FIG. 9a, has the conventional engine12, a planetary transmission 814, and the final drive mechanism 16. Theengine 12 is continuously connected with the input shaft 17. Theplanetary transmission 814 is drivingly connected with final drivemechanism 16 through output shaft 19. The planetary transmission 814includes a planetary gear arrangement 818 that has a first planetarygear set 820, a second planetary gear set 830, a third planetary gearset 840, and fourth planetary gear set 850.

[0179] The planetary gear set 820 includes a sun gear member 822, a ringgear member 824, and a planet carrier assembly member 826. The planetcarrier assembly member 826 includes a plurality of pinion gears 827rotatably mounted on a carrier member 829 and disposed in meshingrelationship with both the sun gear member 822 and the ring gear member824.

[0180] The planetary gear set 830 includes a sun gear member 832, a ringgear member 834, and a planet carrier assembly member 836. The planetcarrier assembly member 836 includes a plurality of intermeshing piniongears 837, 838 rotatably mounted on a carrier member 839 and disposed inmeshing relationship with the ring gear member 834 and the sun gearmember 832, respectively.

[0181] The planetary gear set 840 includes a sun gear member 842, a ringgear member 844, and a planet carrier assembly member 846. The planetcarrier assembly member 846 includes a plurality of pinion gears 847rotatably mounted on a carrier member 849 and disposed in meshingrelationship with both the sun gear member 842 and the ring gear member844.

[0182] The planetary gear set 850 includes a sun gear member 852, a ringgear member 854, and a planet carrier assembly member 856. The planetcarrier assembly member 856 includes a plurality of intermeshing piniongears 857, 858 rotatably mounted on a carrier member 859 and disposed inmeshing relationship with the ring gear member 854 and the sun gearmember 852, respectively.

[0183] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 820, 830, 840 and 850 are divided into firstand second transmission subsets 860, 861 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 860 includes planetary gear sets 820 and 830, andtransmission subset 861 includes planetary gear sets 840 and 850. Theoutput shaft 19 is continuously connected with members of both subsets860 and 861.

[0184] As mentioned above, the first and second input clutches 862, 863are alternatively engaged for transmitting power from the input shaft 17to transmission subset 860 or transmission subset 861. The first andsecond input clutches 862, 863 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratioselection is preselected within the transmission subsets 860, 861 priorto engaging the respective input clutches 862, 863. The preselection isachieved by means of electronically controlled synchronizers. As shown,the planetary gear arrangement includes nine torque transmittingmechanisms 864, 865, 866, 867, 868, 869, 870, 871 and 872. The torquetransmitting mechanisms 864, 865, 869 and 870 comprise brakingsynchronizers, and the torque transmitting mechanisms 866, 867, 868, 871and 872 comprise rotating synchronizers.

[0185] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 860, 861 (i.e. through the clutch862 to the sun gear member 822 and through the clutch 863 to the sungear member 842). The planet carrier assembly member 826 is continuouslyconnected with the sun gear member 832 through the interconnectingmember 874. The planet carrier assembly member 846 is continuouslyconnected with the ring gear member 834, the sun gear member 852 and theoutput shaft 19 through the interconnecting member 876.

[0186] The planet carrier assembly member 826 is selectively connectablewith the transmission housing 880 through the braking synchronizer 864.The planet carrier assembly member 836 is selectively connectable withthe transmission housing 880 through the braking synchronizer 865. Thering gear member 824 is selectively connectable with the planet carrierassembly member 836 through the rotating synchronizer 866. The ring gearmember 824 is selectively connectable with the planet carrier assemblymember 826 through the rotating synchronizer 867. The sun gear member822 is selectively connectable with the planet carrier assembly member836 through the rotating synchronizer 868. The ring gear member 854 isselectively connectable with the transmission housing 880 through thebraking synchronizer 869. The planet carrier assembly member 856 isselectively connectable with the transmission housing 880 through thebraking synchronizer 870. The ring gear member 844 is selectivelyconnectable with the ring gear member 854 through the rotatingsynchronizer 871. The ring gear member 844 is selectively connectablewith the planet carrier assembly member 856 through the rotatingsynchronizer 872.

[0187] As shown in FIG. 9b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide seven forwardspeed ratios and a reverse speed ratio. A sample of numerical values forthe individual ratios is also given in the truth table of FIG. 9b. Thesenumerical values have been calculated using the ring gear/sun gear toothratios also given by way of example in FIG. 9b. The R1/S1 value is thetooth ratio of the planetary gear set 820; the R2/S2 value is the toothratio of planetary gear set 830; the R3/S3 value is the tooth ratio ofthe planetary gear set 840; and the R4/S4 value is the tooth ratio ofthe planetary gear set 850. FIG. 9b also describes the ratio stepsbetween adjacent forward ratios and between the reverse and firstforward ratio. For example, the ratio step between the first and secondforward ratios is 1.62.

[0188] Those skilled in the art will recognize that the numerical valuesof the reverse, second and sixth forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets820, 830. The numerical values of the first and fifth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 840, 850. The numerical value of the thirdforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 840. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 830. The numerical value of the seventhforward speed ratio is 1.

[0189] Referring to FIG. 10a, a powertrain 910 is shown having aconventional engine 12, a planetary transmission 914, and a conventionalfinal drive mechanism 16. The planetary transmission 914 includes aninput shaft 17 connected with the engine 12, a planetary geararrangement 918, and an output shaft 19 continuously connected with thefinal drive mechanism 16. The planetary gear arrangement 918 includesfour planetary gear sets 920, 930, 940 and 950.

[0190] The planetary gear set 920 includes a sun gear member 922, a ringgear member 924, and a planet carrier assembly member 926. The planetcarrier assembly member 926 includes a plurality of intermeshing piniongears 927, 928 rotatably mounted on a carrier member 929 and disposed inmeshing relationship with the ring gear member 924 and the sun gearmember 922, respectively.

[0191] The planetary gear set 930 includes a sun gear member 932, a ringgear member 934, and a planet carrier assembly member 936. The planetcarrier assembly member 936 includes a plurality of pinion gears 937rotatably mounted on a carrier member 939 and disposed in meshingrelationship with both the sun gear member 932 and the ring gear member934.

[0192] The planetary gear set 940 includes a sun gear member 942, a ringgear member 944, and a planet carrier assembly member 946. The planetcarrier assembly member 946 includes a plurality of pinion gears 947rotatably mounted on a carrier member 949 and disposed in meshingrelationship with both the sun gear member 942 and the ring gear member944.

[0193] The planetary gear set 950 includes a sun gear member 952, a ringgear member 954, and a planet carrier assembly member 956. The planetcarrier assembly member 956 includes a plurality of intermeshing piniongears 957, 958 rotatably mounted on a carrier member 959 and disposed inmeshing relationship with the ring gear member 954 and the sun gearmember 952, respectively.

[0194] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 920, 930, 940 and 950 are divided into firstand second transmission subsets 960, 961 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 960 includes planetary gear sets 920 and 930, andtransmission subset 961 includes planetary gear sets 940 and 950. Theoutput shaft 19 is continuously connected with members of both subsets960 and 961.

[0195] As mentioned above, the first and second input clutches 962, 963are alternatively engaged for transmitting power from the input shaft 17to transmission subset 960 or transmission subset 961. The first andsecond input clutches 962, 963 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 960, 961 prior to engagingthe respective input clutches 962, 963. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms964, 965, 966, 967, 968, 969, 970, 971 and 972. The torque transmittingmechanisms 964, 965, 969 and 970 comprise braking synchronizers, and thetorque transmitting mechanisms 966, 967, 968, 971 and 972 compriserotating synchronizers.

[0196] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 960, 961 (i.e. through the clutch962 to the sun gear member 922 and through the clutch 963 to the sungear member 942). The planet carrier assembly member 926 is continuouslyconnected with the sun gear member 932 through the interconnectingmember 974. The planet carrier assembly member 946 is continuouslyconnected with the ring gear member 934, the sun gear member 952 and theoutput shaft 19 through the interconnecting member 976. The planetcarrier assembly member 926 is selectively connectable with thetransmission housing 980 through the braking synchronizer 964. Theplanet carrier assembly member 936 is selectively connectable with thetransmission housing 980 through the braking synchronizer 965. The ringgear member 924 is selectively connectable with the planet carrierassembly member 936 through the rotating synchronizer 966. The ring gearmember 924 is selectively connectable with the planet carrier assemblymember 926 through the rotating synchronizer 967. The sun gear member922 is selectively connectable with the planet carrier assembly member936 through the rotating synchronizer 968. The ring gear member 954 isselectively connectable with the transmission housing 980 through thebraking synchronizer 969. The planet carrier assembly member 956 isselectively connectable with the transmission housing 980 through thebraking synchronizer 970. The ring gear member 944 is selectivelyconnectable with the ring gear member 954 through the rotatingsynchronizer 971. The ring gear member 944 is selectively connectablewith the planet carrier assembly member 956 through the rotatingsynchronizer 972.

[0197] As shown in FIG. 10b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The truth table also provides aset of examples for the numerical values for each of the reverse andforward speed ratios. These numerical values have been determinedutilizing the ring gear/sun gear tooth ratios given in FIG. 10b. TheR1/S1 value is the tooth ratio of the planetary gear set 920; the R2/S2value is the tooth ratio of the planetary gear set 930; the R3/S3 valueis the tooth ratio of the planetary gear set 940; and the R4/S4 value isthe tooth ratio of the planetary gear set 950.

[0198] Those skilled in the art, upon reviewing the engagementcombinations, will recognize that the numerical values of the reverseand sixth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 930. The numericalvalues of the first and third forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets940, 950. The numerical values of the second and fourth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 920, 930. The numerical value of the fifthforward speed ratio is 1.

[0199] Referring to FIG. 11a, a powertrain 1010 is shown having aconventional engine 12, a planetary transmission 1014, and aconventional final drive mechanism 16. The planetary transmission 1014includes an input shaft 17 connected with the engine 12, a planetarygear arrangement 1018, and an output shaft 19 continuously connectedwith the final drive mechanism 16. The planetary gear arrangement 1018includes four planetary gear sets 1020, 1030, 1040 and 1050.

[0200] The planetary gear set 1020 includes a sun gear member 1022, aring gear member 1024, and a planet carrier assembly member 1026. Theplanet carrier assembly member 1026 includes a plurality of pinion gears1027 rotatably mounted on a carrier member 1029 and disposed in meshingrelationship with both the sun gear member 1022 and the ring gear member1024.

[0201] The planetary gear set 1030 includes a sun gear member 1032, aring gear member 1034, and a planet carrier assembly member 1036. Theplanet carrier assembly member 1036 includes a plurality of intermeshingpinion gears 1037, 1038 rotatably mounted on a carrier member 1039 anddisposed in meshing relationship with the ring gear member 1034 and thegear member 1032, respectively.

[0202] The planetary gear set 1040 includes a sun gear member 1042, aring gear member 1044, and a planet carrier assembly member 1046. Theplanet carrier assembly member 1046 includes a plurality of pinion gears1047 rotatably mounted on a carrier member 1049 and disposed in meshingrelationship with both the sun gear member 1042 and the ring gear member1044.

[0203] The planetary gear set 1050 includes a sun gear member 1052, aring gear member 1054, and a planet carrier assembly member 1056. Theplanet carrier assembly member 1056 includes a plurality of intermeshingpinion gears 1057, 1058 rotatably mounted on a carrier member 1059 anddisposed in meshing relationship with the ring gear member 1054 and thesun gear member 1052, respectively.

[0204] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 1020, 1030, 1040 and 1050 are divided intofirst and second transmission subsets 1060, 1061 which are alternativelyengaged to provide odd number and even number speed ranges,respectively. Transmission subset 1060 includes planetary gear sets 1020and 1030, and transmission subset 1061 includes planetary gear sets 1040and 1050. The output shaft 19 is continuously connected with members ofboth subsets 1060 and 1061.

[0205] As mentioned above, the first and second input clutches 1062,1063 are alternatively engaged for transmitting power from the inputshaft 17 to transmission subset 1060 or transmission subset 1061. Thefirst and second input clutches 1062, 1063 are controlledelectronically, and the disengaged input clutch is gradually engagedwhile the engaged input clutch is gradually disengaged to facilitatetransfer of power from one transmission subset to another. In thismanner, shift quality is maintained, as in an automatic transmission,while providing better fuel economy because no torque converter isrequired, and hydraulics associated with “wet” clutching are eliminated.All speed ratios are preselected within the transmission subsets 1060,1061 prior to engaging the respective input clutches 1062, 1063. Thepreselection is achieved by means of electronically controlledsynchronizers. As shown, the planetary gear arrangement includes ninetorque transmitting mechanisms 1064, 1065, 1066, 1067, 1068, 1069, 1070,1071 and 1072. The torque transmitting mechanisms 1064, 1065, 1069 and1070 comprise braking synchronizers, and the torque transmittingmechanisms 1066, 1067, 1068, 1071 and 1072 comprise rotatingsynchronizers.

[0206] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 1060, 1061 (i.e. through theclutch 1062 to the sun gear member 1022 and through the clutch 1063 tothe sun gear member 1042). The planet carrier assembly member 1026 iscontinuously connected with the sun gear member 1032 through theinterconnecting member 1074. The planet carrier assembly member 1046 iscontinuously connected with the ring gear member 1034, the sun gearmember 1052 and the output shaft 19 through the interconnecting member1076.

[0207] The planet carrier assembly member 1026 is selectivelyconnectable with the transmission housing 1080 through the brakingsynchronizer 1064. The ring gear member 1024 is selectively connectablewith the transmission housing 1080 through the braking synchronizer1065. The ring gear member 1024 is selectively connectable with theplanet carrier assembly member 1036 through the rotating synchronizer1066. The sun gear member 1022 is selectively connectable with theplanet carrier assembly member 1036 through the rotating synchronizer1067. The ring gear member 1034 is selectively connectable with theplanet carrier assembly member 1036 through the rotating synchronizer1068. The ring gear member 1054 is selectively connectable with thetransmission housing 1080 through the braking synchronizer 1069. Theplanet carrier assembly member 1056 is selectively connectable with thetransmission housing 1080 through the braking synchronizer 1070. Thering gear member 1044 is selectively connectable with the ring gearmember 1054 through the rotating synchronizer 1071. The ring gear member1044 is selectively connectable with the planet carrier assembly member1056 through the rotating synchronizer 1072.

[0208] As shown in FIG. 11b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The truth table also provides aset of examples for the numerical values for each of the reverse andforward speed ratios. These numerical values have been determinedutilizing the ring gear/sun gear tooth ratios given in FIG. 11b. TheR1/S1 value is the tooth ratio of the planetary gear set 1020; the R2/S2value is the tooth ratio of the planetary gear set 1030; the R3/S3 valueis the tooth ratio of the planetary gear set 1040; and the R4/S4 valueis the tooth ratio of the planetary gear set 1050.

[0209] Those skilled in the art, upon reviewing the engagementcombinations, will recognize that the numerical values of the reverse,first and fifth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 1020, 1030. Thenumerical values of the second and fourth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1040, 1050. The numerical value of the third forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 1020. The numerical value of the sixth forwardspeed ratio is 1.

[0210]FIG. 12a shows a powertrain 1110 having a conventional engine 12,a planetary transmission 1114, and a conventional final drive mechanism16. The planetary transmission 1114 includes an input shaft 17 connectedwith the engine 12, a planetary gear arrangement 1118, and an outputshaft 19 connected with the final drive mechanism 16. The planetary geararrangement 118 includes four planetary gear sets 1120, 1130, 1140 and1150.

[0211] The planetary gear set 1120 includes a sun gear member 1122, aring gear member 1124, and a planet carrier assembly member 1126. Theplanet carrier assembly member 1126 includes a plurality of pinion gears1127 rotatably mounted on a carrier member 1129 and disposed in meshingrelationship with both the sun gear member 1122 and the ring gear member1124.

[0212] The planetary gear set 1130 includes a sun gear member 1132, aring gear member 1134, and a planet carrier assembly member 1136. Theplanet carrier assembly member 1136 includes a plurality of intermeshingpinion gears 1137 rotatably mounted on a carrier member 1139 anddisposed in meshing relationship with the sun gear member 1132 and thering gear member 1134.

[0213] The planetary gear set 1140 includes a sun gear member 1142, aring gear member 1144, and a planet carrier assembly member 1146. Theplanet carrier assembly member 1146 includes a plurality of intermeshingpinion gears 1147, 1148 rotatably mounted on a carrier member 1149 anddisposed in meshing relationship with the ring gear member 1144 and thesun gear member 1142, respectively.

[0214] The planetary gear set 1150 includes a sun gear member 1152, aring gear member 1154, and a planet carrier assembly member 1156. Theplanet carrier assembly member 1156 includes a plurality of intermeshingpinion gears 1157, 1158 rotatably mounted on a carrier member 1159 anddisposed in meshing relationship with the ring gear member 1154 and thesun gear member 1152, respectively.

[0215] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 1120, 1130, 1140 and 1150 are divided intofirst and second transmission subsets 1160, 1161 which are alternativelyengaged to provide odd number and even number speed ranges,respectively. Transmission subset 1160 includes planetary gear sets 1120and 1130, and transmission subset 1161 includes planetary gear sets 1140and 1150. The output shaft 19 is continuously connected with members ofboth subsets 1160 and 1161.

[0216] As mentioned above, the first and second input clutches 1162,1163 are alternatively engaged for transmitting power from the inputshaft 17 to transmission subset 1160 or transmission subset 1161. Thefirst and second input clutches 162, 163 are controlled electronically,and the disengaged input clutch is gradually engaged while the engagedinput clutch is gradually disengaged to facilitate transfer of powerfrom one transmission subset to another. In this manner, shift qualityis maintained, as in an automatic transmission, while providing betterfuel economy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 1160, 1161 prior to engagingthe respective input clutches 1162, 1163. The preselection is achievedby means of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms1164, 1165, 1166, 1167, 1168, 1169, 1170, 1171 and 1172. The torquetransmitting mechanisms 1164, 1165, 1169 and 1170 comprise brakingsynchronizers, and the torque transmitting mechanisms 1166, 1167, 1168,1171 and 1172 comprise rotating synchronizers.

[0217] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 1160, 1161 (i.e. through theclutch 1162 to the sun gear member 1132 and through the clutch 1163 tothe sun gear member 1142). The planet carrier assembly member 1126 iscontinuously connected with the ring gear member 1134 through theinterconnecting member 1174. The planet carrier assembly member 1146 iscontinuously connected with the ring gear members 1124, 1154 and theoutput shaft 19 through the interconnecting member 1176.

[0218] The planet carrier assembly member 1126 is selectivelyconnectable with the transmission housing 1180 through the brakingsynchronizer 1164. The sun gear member 1122 is selectively connectablewith the transmission housing 1180 through the braking synchronizer1165. The planet carrier assembly member 1136 is selectively connectablewith the sun gear member 1132 through the rotating synchronizer 1166.The ring gear member 1124 is selectively connectable with the planetcarrier assembly member 1136 through the rotating synchronizer 1167. Thesun gear member 1122 is selectively connectable with the sun gear member1132 through the rotating synchronizer 1168. The planet carrier assemblymember 1156 is selectively connectable with the transmission housing1180 through the braking synchronizer 1169. The sun gear member 1152 isselectively connectable with the transmission housing 1180 through thebraking synchronizer 1170. The ring gear member 1144 is selectivelyconnectable with the planet carrier assembly member 1156 through therotating synchronizer 1171. The ring gear member 1144 is selectivelyconnectable with the sun gear member 1152 through the rotatingsynchronizer 1172.

[0219] As shown in FIG. 12b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

[0220] Those skilled in the art will recognize that the numerical valuesof the reverse and sixth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratio of the planetary gear set 1120. Thenumerical values of the first and third forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1140, 1150. The numerical value of the secondforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 1130. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratios of the planetary gear sets 1120, 1130. The numerical value of thefifth forward speed ratio is 1.

[0221] As set forth above, the truth table of FIG. 12b describes theengagement sequence of the torque transmitting mechanisms utilized toprovide a reverse drive ratio and six forward speed ratios. The truthtable also provides an example of the ratios that can be attained withthe family members shown in FIG. 12a utilizing the sample tooth ratiosgiven in FIG. 12b. The R1/S1 value is the tooth ratio of the planetarygear set 1120; the R2/S2 value is the tooth ratio of the planetary gearset 1130; the R3/S3 value is the tooth ratio of the planetary gear set1140; and the R4/S4 value is the tooth ratio of the planetary gear set1150. Also shown in FIG. 12b are the ratio steps between single stepratios in the forward direction as well as the reverse to first ratiostep. For example, the first to second step ratio is 1.65.

[0222] Turning the FIG. 13a, a powertrain 1210 having a conventionalengine 12, a planetary transmission 1214, and conventional final drivemechanism 16 is shown.

[0223] The planetary transmission 1214 includes an input shaft 17continuously connected with the engine 12, a planetary gear arrangement1218, and an output shaft 19 continuously connected with the final drivemechanism 16. The planetary gear arrangement 1218 includes fourplanetary gear sets 1220, 1230, 1240 and 1250.

[0224] The planetary gear set 1220 includes a sun gear member 1222, aring gear member 1224, and a planet carrier assembly member 1226. Theplanet carrier assembly member 1226 includes a plurality of pinion gears1227 rotatably mounted on a carrier member 1229 and disposed in meshingrelationship with both the sun gear member 1222 and the ring gear member1224.

[0225] The planetary gear set 1230 includes a sun gear member 1232, aring gear member 1234, and a planet carrier assembly member 1236. Theplanet carrier assembly member 1236 includes a plurality of intermeshingpinion gears 1237, 1238 rotatably mounted on a carrier member 1239 anddisposed in meshing relationship with the ring gear member 1234 and thesun gear member 1232, respectively.

[0226] The planetary gear set 1240 includes a sun gear member 1242, aring gear member 1244, and a planet carrier assembly member 1246. Theplanet carrier assembly member 1246 includes a plurality of pinion gears1247 rotatably mounted on a carrier member 1249 and disposed in meshingrelationship with both the sun gear member 1242 and the ring gear member1244.

[0227] The planetary gear set 1250 includes a sun gear member 1252, aring gear member 1254, and a planet carrier assembly member 1256. Theplanet carrier assembly member 1256 includes a plurality of intermeshingpinion gears 1257, 1258 rotatably mounted on a carrier member 1259 anddisposed in meshing relationship with the ring gear member 1254 and thesun gear member 1252, respectively.

[0228] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 1220, 1230, 1240 and 1250 are divided intofirst and second transmission subsets 1260, 1261 which are alternativelyengaged to provide odd number and even number speed ranges,respectively. Transmission subset 1260 includes planetary gear sets 1220and 1230, and transmission subset 1261 includes planetary gear sets 1240and 1250. The output shaft 19 is continuously connected with members ofboth subsets 1260 and 1261.

[0229] As mentioned above, the first and second input clutches 1262,1263 are alternatively engaged for transmitting power from the inputshaft 17 to transmission subset 1260 or transmission subset 1261. Thefirst and second input clutches 1262, 1263 are controlledelectronically, and the disengaged input clutch is gradually engagedwhile the engaged input clutch is gradually disengaged to facilitatetransfer of power from one transmission subset to another. In thismanner, shift quality is maintained, as in an automatic transmission,while providing better fuel economy because no torque converter isrequired, and hydraulics associated with “wet” clutching are eliminated.All speed ratios are preselected within the transmission subsets 1260,261 prior to engaging the respective input clutches 1262, 1263. Thepreselection is achieved by means of electronically controlledsynchronizers. As shown, the planetary gear arrangement includes ninetorque transmitting mechanisms 1264, 1265, 1266, 1267, 1268, 1269, 1270,1271 and 1272. The torque transmitting mechanisms 1264, 1265, 1269 and1270 comprise braking synchronizers, and the torque transmittingmechanisms 1266, 1267, 1268, 1271 and 1272 comprise rotatingsynchronizers.

[0230] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 1260, 1261 (i.e. through theclutch 1262 to the sun gear member 1222 and through the clutch 1263 tothe sun gear member 1242). The ring gear member 1224 is continuouslyconnected with the sun gear member 1232 through the interconnectingmember 1274. The planet carrier assembly member 1246 is continuouslyconnected with the ring gear member 1234, the sun gear member 1252 andthe output shaft 19 through the interconnecting member 1276.

[0231] The ring gear member 1224 is selectively connectable with thetransmission housing 1280 through the braking synchronizer 1264. Theplanet carrier assembly member 1226 is selectively connectable with thetransmission housing 1280 through the braking synchronizer 1265. Theplanet carrier assembly member 1226 is selectively connectable with theplanet carrier assembly member 1236 through the rotating synchronizer1266. The sun gear member 1222 is selectively connectable with theplanet carrier assembly member 1236 through the rotating synchronizer1267. The ring gear member 1234 is selectively connectable with theplanet carrier assembly member 1236 through the rotating synchronizer1268. The ring gear member 1254 is selectively connectable with thetransmission housing 1280 through the braking synchronizer 1269. Theplanet carrier assembly member 1256 is selectively connectable with thetransmission housing 1280 through the braking synchronizer 1270. Thering gear member 1244 is selectively connectable with the ring gearmember 1254 through the rotating synchronizer 1271. The ring gear member1244 is selectively connectable with the planet carrier assembly member1256 through the rotating synchronizer 1272.

[0232] As shown in FIG. 13b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide seven forwardspeed ratios and a reverse speed ratio.

[0233] Those skilled in the art will recognize that the numerical valuesof the reverse, first and third forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets1220, 1230. The numerical values of the second and sixth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 1240, 1250. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 1240. The numerical value of the fifthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 1230. The numerical value of the seventhforward speed ratio is 1.

[0234] As previously set forth, the truth table of FIG. 13b describesthe combinations of engagements utilized for seven forward speed ratiosand one reverse speed ratio. The truth table also provides an example ofspeed ratios that are available with the family member described above.These examples of speed ratios are determined the tooth ratios given inFIG. 13b. The R1/S1 value is the tooth ratio of the planetary gear set1220; the R2/S2 value is the tooth ratio of the planetary gear set 1230;the R3/S3 value is the tooth ratio of the planetary gear set 1240; andthe R4/S4 value is the tooth ratio of the planetary gear set 1250. Alsodepicted in FIG. 13b is a chart representing the ratio steps betweenadjacent forward speed ratios and the reverse speed ratio. For example,the first to second ratio interchange has a step of 1.43.

[0235] A powertrain 1310, shown in FIG. 14a, includes the engine 12, aplanetary transmission 1314, and the final drive mechanism 16. Theplanetary transmission 1314 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 1318, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 1318 includes four planetary gearsets 1320, 1330, 1340 and 1350.

[0236] The planetary gear set 1320 includes a sun gear member 1322, aring gear member 1324, and a planet carrier assembly member 1326. Theplanet carrier assembly member 1326 includes a plurality of intermeshingpinion gears 1327, 1328 rotatably mounted on a carrier member 1329 anddisposed in meshing relationship with the ring gear member 1324 and thesun gear member 1322, respectively.

[0237] The planetary gear set 1330 includes a sun gear member 1332, aring gear member 1334, and a planet carrier assembly member 1336. Theplanet carrier assembly member 1336 includes a plurality of pinion gears1337 rotatably mounted on a carrier member 1339 and disposed in meshingrelationship with both the sun gear member 1332 and the ring gear member1334.

[0238] The planetary gear set 1340 includes a sun gear member 1342, aring gear member 1344, and a planet carrier assembly member 1346. Theplanet carrier assembly member 1346 includes a plurality of pinion gears1347 rotatably mounted on a carrier member 1349 and disposed in meshingrelationship with both the sun gear member 1342 and the ring gear member1344.

[0239] The planetary gear set 1350 includes a sun gear member 1352, aring gear member 1354, and a planet carrier assembly member 1356. Theplanet carrier assembly member 1356 includes a plurality of intermeshingpinion gears 1357, 1358 rotatably mounted on a carrier member 1359 anddisposed in meshing relationship with the ring gear member 1354 and thesun gear member 1352, respectively.

[0240] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 1320, 1330, 1340 and 1350 are divided intofirst and second transmission subsets 1360, 1361 which are alternativelyengaged to provide odd number and even number speed ranges,respectively. Transmission subset 1360 includes planetary gear sets 1320and 1330, and transmission subset 1361 includes planetary gear sets 1340and 1350. The output shaft 19 is continuously connected with members ofboth subsets 1360 and 1361.

[0241] As mentioned above, the first and second input clutches 1362,1363 are alternatively engaged for transmitting power from the inputshaft 17 to transmission subset 1360 or transmission subset 1361. Thefirst and second input clutches 1362, 1363 are controlledelectronically, and the disengaged input clutch is gradually engagedwhile the engaged input clutch is gradually disengaged to facilitatetransfer of power from one transmission subset to another. In thismanner, shift quality is maintained, as in an automatic transmission,while providing better fuel economy because no torque converter isrequired, and hydraulics associated with “wet” clutching are eliminated.All speed ratios are preselected within the transmission subsets 1360,1361 prior to engaging the respective input clutches 1362, 1363. Thepreselection is achieved by means of electronically controlledsynchronizers. As shown, the planetary gear arrangement includes ninetorque transmitting mechanisms 1364, 1365, 1366, 1367, 1368, 1369, 1370,1371 and 1372. The torque transmitting mechanisms 1364, 1365, 1369 and1370 comprise braking synchronizers, and the torque transmittingmechanisms 1366, 1367, 1368, 1371 and 1372 comprise rotatingsynchronizers.

[0242] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 1360, 1361 (i.e. through theclutch 1362 to the sun gear member 1332 and through the clutch 1363 tothe sun gear member 1342). The sun gear member 1322 is continuouslyconnected with the planet carrier assembly member 1336 through theinterconnecting member 1374. The planet carrier assembly member 1346 iscontinuously connected with the ring gear member 1324, the sun gearmember 1352 and the output shaft 19 through the interconnecting member1376.

[0243] The sun gear member 1322 is selectively connectable with thetransmission housing 1380 through the braking synchronizer 1364. Theplanet carrier assembly member 1326 is selectively connectable with thetransmission housing 1380 through the braking synchronizer 1365. Theplanet carrier assembly member 1326 is selectively connectable with thering gear member 1334 through the rotating synchronizer 1366. The ringgear member 1324 is selectively connectable with the ring gear member1334 through the rotating synchronizer 1367. The ring gear member 1334is selectively connectable with the sun gear member 1332 through therotating synchronizer 1368. The ring gear member 1354 is selectivelyconnectable with the transmission housing 1380 through the brakingsynchronizer 1369. The planet carrier assembly member 1356 isselectively connectable with the transmission housing 1380 through thebraking synchronizer 1370. The ring gear member 1344 is selectivelyconnectable with the ring gear member 1354 through the rotatingsynchronizer 1371. The ring gear member 1344 is selectively connectablewith the planet carrier assembly member 1356 through the rotatingsynchronizer 1372.

[0244] The truth table shown in FIG. 14b describes the engagementcombination and engagement sequence necessary to provide the reversedrive ratio and seven forward speed ratios. A sample of the numericalvalues for the ratios is also provided in the truth table of FIG. 14b.These values are determined utilizing the ring gear/sun gear toothratios also given in FIG. 14b. The R1/S1 value is the tooth ratio forthe planetary gear set 1320; the R2/S2 value is the tooth ratio for theplanetary gear set 1330; the R3/S3 value is the tooth ratio for theplanetary gear set 1340; and the R4/S4 value is the tooth ratio for theplanetary gear set 1350. Also given in FIG. 14b is a chart describingthe step ratios between the adjacent forward speed ratios and thereverse to first forward speed ratio. For example, the first to secondforward speed ratio step is 1.73.

[0245] Those skilled in the art will recognize that the numerical valuesof the reverse, second and fourth forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets1320, 1330. The numerical values of the first and fifth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 1340, 1350. The numerical value of the thirdforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 1340. The numerical value of the sixthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 1320. The numerical value of the seventhforward speed ratio is 1.

[0246] A powertrain 1410 shown in FIG. 15a includes a conventionalengine 12, a planetary transmission 1414, and a conventional final drivemechanism 16. The planetary transmission 1414 includes an input shaft 17connected with the engine 12, a planetary gear arrangement 1418, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 1418 includes four planetary gearsets 1420, 1430, 1440 and 1450.

[0247] The planetary gear set 1420 includes a sun gear member 1422, aring gear member 1424, and a planet carrier assembly member 1426. Theplanet carrier assembly member 1426 includes a plurality of intermeshingpinion gears 1427, 1428 rotatably mounted on a carrier member 1429 anddisposed in meshing relationship with the ring gear member 1424 and thesun gear member 1422, respectively.

[0248] The planetary gear set 1430 includes a sun gear member 1432, aring gear member 1434, and a planet carrier assembly member 1436. Theplanet carrier assembly member 1436 includes a plurality of intermeshingpinion gears 1437, 1438 rotatably mounted on a carrier member 1439 anddisposed in meshing relationship with the ring gear member 1434 and thesun gear member 1432, respectively.

[0249] The planetary gear set 1440 includes a sun gear member 1442, aring gear member 1444, and a planet carrier assembly member 1446. Theplanet carrier assembly member 1446 includes a plurality of pinion gears1447 rotatably mounted on a carrier member 1449 and disposed in meshingrelationship with both the sun gear member 1442 and the ring gear member1444.

[0250] The planetary gear set 1450 includes a sun gear member 1452, aring gear member 1454, and a planet carrier assembly member 1456. Theplanet carrier assembly member 1456 includes a plurality of intermeshingpinion gears 1457, 1458 rotatably mounted on a carrier member 1459 anddisposed in meshing relationship with the ring gear member 1454 and thesun gear member 1452, respectively.

[0251] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 1420, 1430, 1440 and 1450 are divided intofirst and second transmission subsets 1460, 1461 which are alternativelyengaged to provide odd number and even number speed ranges,respectively. Transmission subset 1460 includes planetary gear sets 1420and 1430, and transmission subset 1461 includes planetary gear sets 1440and 1450. The output shaft 19 is continuously connected with members ofboth subsets 1460 and 1461.

[0252] As mentioned above, the first and second input clutches 1462,1463 are alternatively engaged for transmitting power from the inputshaft 17 to transmission subset 1460 or transmission subset 1461. Thefirst and second input clutches 1462, 1463 are controlledelectronically, and the disengaged input clutch is gradually engagedwhile the engaged input clutch is gradually disengaged to facilitatetransfer of power from one transmission subset to another. In thismanner, shift quality is maintained, as in an automatic transmission,while providing better fuel economy because no torque converter isrequired, and hydraulics associated with “wet” clutching are eliminated.All speed ratios are preselected within the transmission subsets 1460,1461 prior to engaging the respective input clutches 1462, 1463. Thepreselection is achieved by means of electronically controlledsynchronizers. As shown, the planetary gear arrangement includes ninetorque transmitting mechanisms 1464, 1465, 1466, 1467, 1468, 1469, 1470,1471 and 1472. The torque transmitting mechanisms 1464, 1465, 1469 and1470 comprise braking synchronizers, and the torque transmittingmechanisms 1466, 1467, 1468, 1471 and 1472 comprise rotatingsynchronizers.

[0253] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 1460, 1461 (i.e. through theclutch 1462 to the sun gear member 1422 and through the clutch 1463 tothe sun gear member 1442). The ring gear member 1424 is continuouslyconnected with the sun gear member 1432 through the interconnectingmember 1474. The planet carrier assembly member 1446 is continuouslyconnected with the ring gear member 1434, the sun gear member 1452 andthe output shaft 19 through the interconnecting member 1476.

[0254] The ring gear member 1424 is selectively connectable with thetransmission housing 1480 through the braking synchronizer 1464. Theplanet carrier assembly member 1426 is selectively connectable with thetransmission housing 1480 through the braking synchronizer 1465. Theplanet carrier assembly member 1426 is selectively connectable with theplanet carrier assembly member 1436 through the rotating synchronizer1466. The sun gear member 1422 is selectively connectable with theplanet carrier assembly member 1436 through the rotating synchronizer1467. The ring gear member 1434 is selectively connectable with theplanet carrier assembly member 1436 through the rotating synchronizer1468. The ring gear member 1454 is selectively connectable with thetransmission housing 1480 through the braking synchronizer 1469. Theplanet carrier assembly member 1456 is selectively connectable with thetransmission housing 1480 through the braking synchronizer 1470. Thering gear member 1444 is selectively connectable with the ring gearmember 1454 through the rotating synchronizer 1471. The ring gear member1444 is selectively connectable with the planet carrier assembly member1456 through the rotating synchronizer 1472.

[0255] As shown in FIG. 15b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide seven forwardspeed ratios and a reverse speed ratio.

[0256]FIG. 15b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first ratio. For example, theratio step between the first and second forward ratios is 1.65. Thoseskilled in the art will recognize that the numerical values of thereverse, second and sixth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 1420,1430. The numerical values of the first and fifth forward speed ratiosare determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1440, 1450. The numerical value of the third forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 1440. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 1420. The numerical value of the seventhforward speed ratio is 1.

[0257]FIGS. 16a and 16 b illustrate a transmission wherein one of thetorque transmitting mechanisms from a previously described configurationis eliminated to realize six forward speed ratios and a reverse speedratio. Specifically, the powertrain 1510, shown in FIG. 16a is identicalto that shown in FIG. 13a, except that the synchronizer 1268 of FIG. 13ahas been eliminated.

[0258] A powertrain 1510, shown in FIG. 16a, includes a conventionalengine 12, a powertrain 1514, and a convention final drive mechanism 16.The powertrain 1514 includes an input shaft 17 connected with the engine12, a planetary gear arrangement 1518, and an output shaft 19continuously connected with the final drive mechanism 16. The planetarygear arrangement 1518 includes four planetary gear sets 1520, 1530, 1540and 1550.

[0259] The planetary gear set 1520 includes a sun gear member 1522, aring gear member 1524, and a planet carrier assembly member 1526. Theplanet carrier assembly member 1526 includes a plurality of pinion gears1527 rotatably mounted on a carrier member 1529 and disposed in meshingrelationship with both the sun gear member 1522 and the ring gear member1524.

[0260] The planetary gear set 1530 includes a sun gear member 1532, aring gear member 1534, and a planet carrier assembly member 1536. Theplanet carrier assembly member 1536 includes a plurality of intermeshingpinion gears 1537, 1538 rotatably mounted on a carrier member 1539 anddisposed in meshing relationship with the ring gear member 1534 and thesun gear member 1532, respectively.

[0261] The planetary gear set 1540 includes a sun gear member 1542, aring gear member 1544, and a planet carrier assembly member 1546. Theplanet carrier assembly member 1546 includes a plurality of pinion gears1547 rotatably mounted on a carrier member 1549 and disposed in meshingrelationship with both the sun gear member 1542 and the ring gear member1544.

[0262] The planetary gear set 1550 includes a sun gear member 1552, aring gear member 1554, and a planet carrier assembly member 1556. Theplanet carrier assembly member 1556 includes a plurality of intermeshingpinion gears 1557, 1558 rotatably mounted on a carrier member 1559 anddisposed in meshing relationship with the ring gear member 1554 and thesun gear member 1552, respectively.

[0263] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 1520, 1530, 1540 and 1550 are divided intofirst and second transmission subsets 1560, 1561 which are alternativelyengaged to provide odd number and even number speed ranges,respectively. Transmission subset 1560 includes planetary gear sets 1520and 1530, and transmission subset 1561 includes planetary gear sets 1540and 1550. The output shaft 19 is continuously connected with members ofboth subsets 1560 and 1561.

[0264] As mentioned above, the first and second input clutches 1562,1563 are alternatively engaged for transmitting power from the inputshaft 17 to transmission subset 1560 or transmission subset 1561. Thefirst and second input clutches 1562, 1563 are controlledelectronically, and the disengaged input clutch is gradually engagedwhile the engaged input clutch is gradually disengaged to facilitatetransfer of power from one transmission subset to another. In thismanner, shift quality is maintained, as in an automatic transmission,while providing better fuel economy because no torque converter isrequired, and hydraulics associated with “wet” clutching are eliminated.All speed ratios are preselected within the transmission subsets 1560,1561 prior to engaging the respective input clutches 1562, 1563. Thepreselection is achieved by means of electronically controlledsynchronizers. As shown, the planetary gear arrangement includes eighttorque transmitting mechanisms 1564, 1565, 1566, 1567, 1569, 1570, 1571and 1572. The torque transmitting mechanisms 1564, 1565, 1569 and 1570comprise braking synchronizers, and the torque transmitting mechanisms1566, 1567, 1571 and 1572 comprise rotating synchronizers.

[0265] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 1560, 1561 (i.e. through theclutch 1562 to the sun gear member 1522 and through the clutch 1563 tothe sun gear member 1542). The ring gear member 1524 is continuouslyconnected with the sun gear member 1532 through the interconnectingmember 1574. The planet carrier assembly member 1546 is continuouslyconnected with the ring gear member 1534, the sun gear member 1552 andthe output shaft 19 through the interconnecting member 1576.

[0266] The ring gear member 1524 is selectively connectable with thetransmission housing 1580 through the braking synchronizer 1564. Theplanet carrier assembly member 1526 is selectively connectable with thetransmission housing 1580 through the braking synchronizer 1565. Theplanet carrier assembly member 1526 is selectively connectable with theplanet carrier assembly member 1536 through the rotating synchronizer1566. The sun gear member 1522 is selectively connectable with theplanet carrier assembly member 1536 through the rotating synchronizer1567. The ring gear member 1554 is selectively connectable with thetransmission housing 1580 through the braking synchronizer 1569. Theplanet carrier assembly member 1556 is selectively connectable with thetransmission housing 1580 through the braking synchronizer 1570. Thering gear member 1544 is selectively connectable with the ring gearmember 1554 through the rotating synchronizer 1571. The ring gear member1544 is selectively connectable with the planet carrier assembly member1556 through the rotating synchronizer 1572.

[0267] As shown in FIG. 16b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The chart of FIG. 16b describesthe ratio steps between adjacent forward speed ratios and the ratio stepbetween the reverse and first forward speed ratio.

[0268] Those skilled in the art, upon reviewing the truth table and theschematic representation of FIG. 16a can determine that the numericalvalues of the reverse, first and third forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1520, 1530. The numerical values of the second andsixth forward speed ratios are determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 1540, 1550. The numericalvalue of the fourth forward speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 1540. The numericalvalue of the fifth forward speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 1530.

[0269] The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 16b. R1/S1 value isthe tooth ratio of the planetary gear set 1520; the R2/S2 value is thetooth ratio of the planetary gear set 1530; the R3/S3 value is the toothratio of the planetary gear set 1540; and the R4/S4 value is the toothratio of the planetary gear set 1550.

[0270]FIGS. 17a and 17 b illustrate a transmission wherein one of thetorque transmitting mechanisms from a previously described configurationis eliminated to realize five forward speed ratios and a reverse speedratio. Specifically, the powertrain 1710, shown in FIG. 17a is identicalto that shown in FIG. 10a, except that the synchronizer 968 of FIG. 13ahas been eliminated.

[0271] A powertrain 1610, shown in FIG. 17a, has the engine and torqueconverter 12, a planetary transmission 1614, and the final drivemechanism 16. The planetary transmission 1614 includes the input shaft17, a planetary gear arrangement 1618, and the output shaft 19. Theplanetary gear arrangement 1618 includes four planetary gear sets 1620,1630, 1640 and 1650.

[0272] The planetary gear set 1620 includes a sun gear member 1622, aring gear member 1624, and a planet carrier assembly member 1626. Theplanet carrier assembly member 1626 includes a plurality of pinion gears1627, 1628 rotatably mounted on a carrier member 1629 and disposed inmeshing relationship with both the sun gear member 1622 and the ringgear member 1624.

[0273] The planetary gear set 1630 includes a sun gear member 1632, aring gear member 1634, and a planet carrier assembly member 1636. Theplanet carrier assembly member 1636 includes a plurality of intermeshingpinion gears 1637 rotatably mounted on a carrier member 1639 anddisposed in meshing relationship with the sun gear member 1632 and thering gear member 1634.

[0274] The planetary gear set 1640 includes a sun gear member 1642, aring gear member 1644, and a planet carrier assembly member 1646. Theplanet carrier assembly member 1646 includes a plurality of pinion gears1647 rotatably mounted on a carrier member 1649 and disposed in meshingrelationship with both the sun gear member 1642 and the ring gear member1644.

[0275] The planetary gear set 1650 includes a sun gear member 1652, aring gear member 1654, and a planet carrier assembly member 1656. Theplanet carrier assembly member 1656 includes a plurality of intermeshingpinion gears 1657, 1658 rotatably mounted on a carrier member 1659 anddisposed in meshing relationship with the ring gear member 1654 and thesun gear member 1652, respectively.

[0276] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 1620, 1630, 1640 and 1650 are divided intofirst and second transmission subsets 1660, 1661 which are alternativelyengaged to provide odd number and even number speed ranges,respectively. Transmission subset 1660 includes planetary gear sets 1620and 1630, and transmission subset 1661 includes planetary gear sets 1640and 1650. The output shaft 19 is continuously connected with members ofboth subsets 1660 and 1661.

[0277] As mentioned above, the first and second input clutches 1662,1663 are alternatively engaged for transmitting power from the inputshaft 17 to transmission subset 1660 or transmission subset 1661. Thefirst and second input clutches 1662, 1663 are controlledelectronically, and the disengaged input clutch is gradually engagedwhile the engaged input clutch is gradually disengaged to facilitatetransfer of power from one transmission subset to another. In thismanner, shift quality is maintained, as in an automatic transmission,while providing better fuel economy because no torque converter isrequired, and hydraulics associated with “wet” clutching are eliminated.All speed ratios are preselected within the transmission subsets 1660,1661 prior to engaging the respective input clutches 1662, 1663. Thepreselection is achieved by means of electronically controlledsynchronizers. As shown, the planetary gear arrangement includes eighttorque transmitting mechanisms 1664, 1665, 1666, 1667, 1669, 1670, 1671and 1672. The torque transmitting mechanisms 1664, 1665, 1669 and 1670comprise braking synchronizers, and the torque transmitting mechanisms1666, 1667, 1671 and 1672 comprise rotating synchronizers.

[0278] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 1660, 1661 (i.e. through inputclutch 1662 to the sun gear member 1622 and through input clutch 1663 tothe sun gear member 1642). The planet carrier assembly member 1626 iscontinuously connected with the sun gear member 1632 through theinterconnecting member 1674. The planet carrier assembly member 1646 iscontinuously connected with the ring gear member 1634, the sun gearmember 1652 and the output shaft 19 through the interconnecting member1676.

[0279] The planet carrier assembly member 1626 is selectivelyconnectable with the transmission housing 1680 through the brakingsynchronizer 1664. The planet carrier assembly member 1636 isselectively connectable with the transmission housing 1680 through thebraking synchronizer 1665. The ring gear member 1624 is selectivelyconnectable with the planet carrier assembly member 1636 through therotating synchronizer 1666. The planet carrier assembly member 1626 isselectively connectable with the ring gear member 1624 through therotating synchronizer 1667. The ring gear member 1654 is selectivelyconnectable with the transmission housing 1680 through the brakingsynchronizer 1669. The planet carrier assembly member 1656 isselectively connectable with the transmission housing 1680 through thebraking synchronizer 1670. The ring gear member 1644 is selectivelyconnectable with the ring gear member 1654 through the rotatingsynchronizer 1671. The ring gear member 1644 is selectively connectablewith the planet carrier assembly member 1656 through the rotatingsynchronizer 1672.

[0280] As shown in FIG. 17b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of at least three to provide sevenforward speed ratios and a reverse speed ratio. The ratio values givenare by way example and are established utilizing the ring gear/sun geartooth ratios given in FIG. 17b. For example, the R1/S2 value is thetooth ratio of the planetary gear set 1620; the R2/S2 value is the toothratio of the planetary gear set 1630; the R3/S3 value is the tooth ratioof the planetary gear set 1640; and the R4/S4 value is the tooth ratioof the planetary gear set 1650. The ratio steps between adjacent forwardratios and the reverse to first ratio are also given in FIG. 17b.

[0281] Those skilled in the art, upon reviewing the truth table and theschematic representation of FIG. 17a, can determine that the numericalvalue of the reverse speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 1630. The numericalvalues of the first and third forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets1640, 1650. The numerical values of the second and fourth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 1620, 1630. The numerical value of the fifthforward speed ratio is 1.

[0282] While the best modes for carrying out the invention have beendescribed in detail, those familiar with the art to which this inventionrelates will recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A multi-speed transmission comprising: an input shaft; an outputshaft; first, second, third and fourth planetary gear sets each havingfirst, second and third members; a first interconnecting membercontinuously interconnecting said first member of said first planetarygear set with said first member of said second planetary gear set; asecond interconnecting member continuously interconnecting a member ofsaid first or second planetary gear set with said first member of saidthird planetary gear set, said first member of said fourth planetarygear set and with said output shaft; a first input clutch selectivelyinterconnecting said input shaft with a member of said first or saidsecond planetary gear set that is not continuously connected with saidoutput shaft; a second input clutch selectively interconnecting saidinput shaft with said second member of said third planetary gear set;first, second and third torque-transmitting mechanisms selectivelyinterconnecting members of said first and second planetary gear setswith other members of said first and second planetary gear sets; fourthand fifth torque-transmitting mechanisms selectively interconnectingmembers of said third planetary gear set with members of said fourthplanetary gear set; sixth and seventh torque-transmitting mechanismsselectively interconnecting members of said first or second planetarygear set, that are not continuously connected with said output shaft orsaid first input clutch, with a stationary member; and eighth and ninthtorque-transmitting mechanisms selectively interconnecting said secondand third members of said fourth planetary gear set with said stationarymember; said input clutches and torque-transmitting mechanisms beingengaged in combinations of at least three to provide at least sixforward speed ratios and a reverse speed ratio.
 2. The transmissiondefined in claim 1, wherein said nine torque-transmitting mechanismscomprise synchronizers.
 3. The transmission defined in claim 1, whereinsaid first, second, third, fourth and fifth torque-transmittingmechanisms comprise rotating synchronizers, and said sixth, seventh,eighth and ninth torque-transmitting mechanisms comprise brakingsynchronizers.
 4. The transmission defined in claim 1, wherein saidfirst input clutch is applied for odd number speed ranges and saidsecond input clutch is applied for even number speed ranges.
 5. Thetransmission defined in claim 1, wherein said first input clutch isapplied for even number speed ranges and said second input clutch isapplied for odd number speed ranges.
 6. The transmission defined inclaim 1, wherein said first input clutch and said second input clutchare interchangeable to shift from odd number speed ranges to even numberspeed ranges, and vice versa.
 7. The transmission defined in claim 1,wherein selected ones of said nine torque-transmitting mechanisms areengaged prior to gear shifting to achieve shifting without torqueinterruptions.
 8. The transmission defined in claim 1, wherein at leasttwo of said synchronizers comprise a double synchronizer to reduce costand package size.
 9. A multi-speed transmission comprising: an inputshaft; an output shaft; first, second, third and fourth planetary gearsets each having first, second and third members; a firstinterconnecting member continuously interconnecting said first member ofsaid first planetary gear set with said first member of said secondplanetary gear set; a second interconnecting member continuouslyinterconnecting a member of said first or second planetary gear set withsaid first member of said third planetary gear set, said first member ofsaid fourth planetary gear set and with said output shaft; a first inputclutch selectively interconnecting said input shaft with a member ofsaid first or said second planetary gear set that is not continuouslyconnected with said output shaft; a second input clutch selectivelyinterconnecting said input shaft with said second member of said thirdplanetary gear set; and nine torque-transmitting mechanisms forselectively interconnecting said members of said first, second, third orfourth planetary gear sets with said first or second input clutch, saidoutput shaft, said first or second interconnecting member, a stationarymember or with other members of said planetary gear sets, said inputclutches and nine torque-transmitting mechanisms being engaged incombinations of at least three to establish at least six forward speedratios and a reverse speed ratio between said input shaft and saidoutput shaft.
 10. The transmission defined in claim 9, wherein first,second and third of said nine torque-transmitting mechanisms areselectively operable for interconnecting members of said first andsecond planetary gear sets with other members of said first and secondplanetary gear sets.
 11. The transmission defined in claim 9, whereinfourth and fifth of said nine torque-transmitting mechanisms areselectively operable for interconnecting members of said third planetarygear set with members of said fourth planetary gear set.
 12. Thetransmission defined in claim 9, wherein sixth and seventh of said ninetorque-transmitting mechanisms are operable for selectivelyinterconnecting members of said first or second planetary gear set thatare not continuously connected with said output shaft and said firstinput clutch with said stationary member.
 13. The transmission definedin claim 9, wherein eighth and ninth of said nine torque-transmittingmechanisms torque-transmitting mechanisms are operable for selectivelyinterconnecting said second and third members of said fourth planetarygear set with said stationary member.
 14. The transmission defined inclaim 9, wherein planet carrier assembly members of a plurality of saidplanetary gear sets are of the single pinion type.
 15. The transmissiondefined in claim 9, wherein planet carrier assembly members of aplurality of said planetary gear sets are of the double pinion type. 16.The transmission defined in claim 9, wherein each of said ninetorque-transmitting mechanisms comprises a synchronizer.
 17. Thetransmission defined in claim 9, wherein said first input clutch isapplied for odd number speed ranges and said second input clutch isapplied for even number speed ranges.
 18. The transmission defined inclaim 9, wherein said first input clutch is applied for even numberspeed ranges and said second input clutch is applied for odd numberspeed ranges.
 19. The transmission defined in claim 9, wherein selectedones of said nine torque-transmitting mechanisms are engaged prior togear shifting to achieve shifting without torque interruptions.
 20. Amulti-speed transmission comprising: an input shaft; an output shaft;first, second, third and fourth planetary gear sets each having first,second and third members; a first interconnecting member continuouslyinterconnecting said first member of said first planetary gear set withsaid first member of said second planetary gear set; a secondinterconnecting member continuously interconnecting a member of saidfirst or second planetary gear set with said first member of said thirdplanetary gear set, said first member of said fourth planetary gear setand with said output shaft; a first input clutch selectivelyinterconnecting said input shaft with a member of said first or saidsecond planetary gear set that is not continuously connected with saidoutput shaft; a second input clutch selectively interconnecting saidinput shaft with said second member of said third planetary gear set;and eight torque-transmitting mechanisms for selectively interconnectingsaid members of said first, second, third or fourth planetary gear setswith said first or second input clutch, said output shaft, said first orsecond interconnecting member, a stationary member or with other membersof said planetary gear sets, said input clutches and eighttorque-transmitting mechanisms being engaged in combinations of at leastthree to establish at least five forward speed ratios and a reversespeed ratio between said input shaft and said output shaft.
 21. Thetransmission defined in claim 20, wherein first and second of said eighttorque-transmitting mechanisms are selectively operable forinterconnecting members of said first and second planetary gear setswith other members of said first and second planetary gear sets.
 22. Thetransmission defined in claim 20, wherein third and fourth of said eighttorque-transmitting mechanisms are selectively operable forinterconnecting members of said third planetary gear set with members ofsaid fourth planetary gear set.
 23. The transmission defined in claim20, wherein fifth and sixth of said eight torque-transmitting mechanismsare operable for selectively interconnecting members of said first orsecond planetary gear set that are not continuously connected with saidoutput shaft or said first input clutch with said stationary member. 24.The transmission defined in claim 20, wherein seventh and eighth of saideight torque-transmitting mechanisms are operable for selectivelyinterconnecting said second or third member of said fourth planetarygear with said stationary member.
 25. The transmission defined in claim20, wherein planet carrier assembly members of a plurality of saidplanetary gear sets are of the single pinion type.
 26. The transmissiondefined in claim 20, wherein planet carrier assembly members of aplurality of said planetary gear sets are of the double pinion type. 27.The transmission defined in claim 20, wherein each of said eighttorque-transmitting mechanisms comprises a synchronizer.
 28. Thetransmission defined in claim 20, wherein said first input clutch isapplied for odd number speed ranges and said second input clutch isapplied for even number speed ranges.
 29. The transmission defined inclaim 20, wherein said first input clutch is applied for even numberspeed ranges and said second input clutch is applied for odd numberspeed ranges.
 30. The transmission defined in claim 20, wherein selectedones of said eight torque-transmitting mechanisms are engaged prior togear shifting to achieve shifting without torque interruptions.